Solid oxide electrolysis cells(SOECs)can effectively convert CO_(2)into high value-added CO fuel.In this paper,Sc-doped Sr_(2)Fe_(1.5)Mo_(0.3)Sc_(0.2)O_(6−δ)(SFMSc)perovskite oxide material is synthesized via solid-p...Solid oxide electrolysis cells(SOECs)can effectively convert CO_(2)into high value-added CO fuel.In this paper,Sc-doped Sr_(2)Fe_(1.5)Mo_(0.3)Sc_(0.2)O_(6−δ)(SFMSc)perovskite oxide material is synthesized via solid-phase method as the cathode for CO_(2)electrolysis by SOECs.XRD confirms that SFMSc exhibits a stable cubic phase crystal structure.The experimental results of TPD,TG,EPR,CO_(2)-TPD further demonstrate that Sc-doping increases the concentration of oxygen vacancy in the material and the chemical adsorption capacity of CO_(2)molecules.Electrochemical tests reveal that SFMSc single cell achieves a current density of 2.26 A/cm^(2) and a lower polarization impedance of 0.32Ω·cm^(2) at 800°C under the applied voltage of 1.8 V.And no significant performance attenuation or carbon deposition is observed after 80 h continuous long-term stability test.This study provides a favorable support for the development of SOEC cathode materials with good electro-catalytic performance and stability.展开更多
Lithium nickel oxide(Li_(2)NiO_(2)),as a sacrificial cathode prelithiation additive,has been used to compensate for the lithium loss for improving the lifespan of lithium-ion batteries(LIBs).However,high-cost Li_(2)Ni...Lithium nickel oxide(Li_(2)NiO_(2)),as a sacrificial cathode prelithiation additive,has been used to compensate for the lithium loss for improving the lifespan of lithium-ion batteries(LIBs).However,high-cost Li_(2)NiO_(2)suffers from inferior delithiation kinetics during the first cycle.Herein,we investigated the effects of the cost-effective copper substituted Li_(2)Ni_(1-x)Cu_(x)O_(2)(x=0,0.2,0.3,0.5,0.7)synthesized by a high-temperature solid-phase method on the structure,morphology,electrochemical performance of graphite‖LiFePO_(4)battery.The X-ray diffraction(XRD)refinement result demonstrated that Cu substitution strategy could be favorable for eliminating the NiO_(x)impurity phase and weakening Li-O bond.Analysis on density of states(DOS)indicates that Cu substitution is good for enhancing the electronic conductivity,as well as reducing the delithi-ation voltage polarization confirmed by electrochemical characterizations.Therefore,the optimal Li_(2)Ni_(0.7)Cu_(0.3)O_(2)delivered a high delithiation capacity of 437 mAh·g^(-1),around 8%above that of the pristine Li_(2)NiO_(2).Furthermore,a graphite‖LiFePO_(4)pouch cell with a nominal capacity of 3000 mAh demonstrated a notably improved reversible capacity,energy density and cycle life through introducing 2 wt%Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive,delivering a 6.2 mAh·g^(-1)higher initial discharge capacity and achieving around 5%improvement in capacity retentnion at 0.5P over 1000 cycles.Additionally,the post-mortem analyses testified that the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive could suppress solid electrolyte interphase(SEI)decomposition and homogenize the Li distribution,which benefits to stabilizing interface between graphite and electrolyte,and alleviating dendritic Li plating.In conclusion,the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive may offer advantages such as lower cost,lower delithiation voltage and higher prelithiation capacity compared with Li_(2)NiO_(2),making it a promising candidate of cathode prelithiation additive for next-generation LIBs.展开更多
This study focuses on using a green reagent scheme of methanesulfonic acid (MSA) and citric acid (CA) to extract valuable metals from the cathodes, aiming to minimize environmental impact during the recycling process....This study focuses on using a green reagent scheme of methanesulfonic acid (MSA) and citric acid (CA) to extract valuable metals from the cathodes, aiming to minimize environmental impact during the recycling process. Leaching studies on LiCoO_(2) identified optimal conditions as follows: 2.4 mol/L MSA, 1.6 mol/L CA, S/L ratio of 80 g/L, leaching temperature of 90oC and leaching time of 6 h. The maximum Co and Li extraction achieved was 92% and 85%, respectively. LiCoO_(2) dissolution in MSA-CA leaching solution is highly impacted by temperature;Avrami equation showed a good fitting for the leaching data. The experimental activation energy of Co and Li was 50.98 kJ/mol and 50.55 kJ/mol, respectively, indicating that it is a chemical reaction-controlled process. Furthermore, cobalt was efficiently recovered from the leachate using oxalic acid, achieving a precipitation efficiency of 99.91% and a high-purity cobalt oxalate product (99.85 wt.%). In the MSA-CA leaching solution, MSA served as a lixiviant, while CA played a key role in reducing Co in LiCoO_(2). The overall organic acid leaching methodology presents an attractive option due to its reduced environmental impact.展开更多
As a cathode material for thermal batteries,NiS_(2)has a high theoretical capacity but low thermal stability.Besides,the poor formability of NiS_(2)powders also restricts the cathode performance of thermal batteries.I...As a cathode material for thermal batteries,NiS_(2)has a high theoretical capacity but low thermal stability.Besides,the poor formability of NiS_(2)powders also restricts the cathode performance of thermal batteries.In this paper,the novel NiS_(2)/SiO_(2)composite material was developed by high temperature vulcanization to improve the thermal stability formability of NiS_(2).The good filling and lubrication of spherical SiO_(2)can improve the thermal conductivity of NiS_(2)electrode.The discharge test shows that the NiS_(2)/SiO_(2)cathode has a stable discharge voltage at a current density of 200 mA/cm^(2),and the activation time is shortened by nearly 20%compared with the NiS_(2)cathode.In addition,due to the favorable thermal insulation protection of SiO_(2),the initial decomposition temperature of NiS_(2)is increased by 30℃after the addition of SiO_(2).The incorporation of SiO_(2)not only effectively improves the thermal stability and electrochemical properties of NiS_(2),but also improves the cold pressing forming performance of the NiS_(2)powder.Therefore,the novel NiS_(2)/SiO_(2)composite material is more suitable for thermal batteries with high stability and fast response,which is of great significance for improving the maneuverability and quality reliability of weapons and equipment.展开更多
Developing in situ spectroelectrochemistry methods,which can provide detailed information about species trans-formation during electrochemical reactions,is very important for studying electrode reaction mechanisms and...Developing in situ spectroelectrochemistry methods,which can provide detailed information about species trans-formation during electrochemical reactions,is very important for studying electrode reaction mechanisms and improving battery performance.Studying real-time changes in the surface of electrode materials during normal operation can be an effective way to assess and optimize the practical performance of electrode materials,thus,in situ and in operando characterization techniques are particularly important.However,batteries are hard to be studied by in situ characterization measurements due to their hermetically sealed shells,and there is still much room for battery characterizations.In this work,a specially designed battery based on the structure of coin cells,whose upper cover was transparent,was constructed.With such a device,acquisition of diffuse reflectance spectra of electrode materials during charging and discharging was realized.This not only provided a simple measurement accessory for diffuse reflectance spectroscopy(DRS),but also complemented in situ characterization techniques for batteries.Taking commonly used cathode materials in lithium-ion batteries(LIBs),including LiFePO_(4)(LFP),NCM811 and LiCoO_(2)(LCO)as examples,we managed tofind out the response relationships of different electrode materials to visible light of different wavelengths under ordinary reflectance illumination conditions.Heterogeneity of different cathode ma-terials on interaction relationships with the lights of different wavelengths was also revealed.This work demonstrated the capability of guiding wavelength selection for different materials and assessing electrochemical performances of in situ diffuse reflectance spectroelectrochemistry.By combining electrochemistry with diffuse reflectance spectroscopy,this work made an effective complementary for spectroelectrochemistry.展开更多
Sodium-ion batteries are economical and environmentally sustainable energy storage batteries.Among them,β-NaMnO_(2),a promising sodium-ion cathode material,is a manganese-based oxide with a corrugated laminar structu...Sodium-ion batteries are economical and environmentally sustainable energy storage batteries.Among them,β-NaMnO_(2),a promising sodium-ion cathode material,is a manganese-based oxide with a corrugated laminar structure,which has attracted significant attention due to its structural robustness and relatively high specific capacity.However,it has short cycle life and poor rate capability.To address these issues,Ti atoms,known for enhancing structural stability,and Cu atoms,which facilitate desodiation,were doped intoβ-NaMnO_(2) by first-principles calculation and crystal orbital Hamilton population(COHP)analysis.β-NaMn_(0.8)Ti_(0.1)Cu_(0.1)O_(2) exhibits a notable increase in reversible specific capacity and remarkable rate properties.Operating at a current density of 0.2C(1C=219 mA·g^(–1))and within a voltage range of 1.8–4.0 V,the modified material delivers an initial discharge capacity of 132 mAh·g^(–1).After charge/discharge testing at current densities of 0.2C,0.5C,1C,3C,and 0.2C,the material still maintains a capacity of 110 mA h·g^(–1).The doping of Ti atoms slows down the changes in the crystal structure,resulting in only minimal variation in the lattice constant c/a during the desodiation process.Mn and Cu engage in reversible redox reactions at voltages below 3.0 V and around 3.5 V,respectively.The extended plateau observed in the discharge curve below 3.0 V signifies that Mn significantly contributes to the overall battery capacity.This study provides insights into modifyingβ-NaMnO_(2) as a cathode material,offering experimental evidence and theoretical guidance for enhancing battery performance in Na-ion batteries.展开更多
The irreversible phase transition and interface side reactions during the cycling process severely limit the large scale application of nickel-rich layered oxides Li[Ni_(x)Co_(y)Mn_(1−x−y)]O_(2)(NCM,x>0.8).Herein,w...The irreversible phase transition and interface side reactions during the cycling process severely limit the large scale application of nickel-rich layered oxides Li[Ni_(x)Co_(y)Mn_(1−x−y)]O_(2)(NCM,x>0.8).Herein,we have designed LiNi_(0.8)Co_(0.1)Mn 0.1 O_(2)cathodes modified by Nb/Al co-doping and LiNbO_(3)/LiAlO_(2)composite coating.Detailed characterization reveals that Nb/Al co-doping can stabilize the crystal structure of the cathodes and expand the layer spacing of the layered lattice,thereby increasing the diffusion rate and reversibility of Li^(+).And the composite coatings can improve the electrochemical kinetic and inhibit the erosion of acidic substances by hindering direct contact between the cathodes and electrolyte.As a result,the Ni-rich cathodes with dual modification can still exhibit a higher capacity of 184.02 mA·h/g after 100 cycles with a capacity retention of up to 98.1%,and can still release a capacity of 161.6 mA·h/g at a high rate of 7 C,meanwhile,it shows excellent thermal stability compared to bare NCM.This work provides a new perspective for enhancing electrochemical properties of cathodes through integrated strategies.展开更多
The effects of NOx(in a ratio of NO∶NO2=9∶1) and SO2in cathode streamonthe performance of a single proton ex-change membrane fuel cell(PEMFC) were investigated.NOxwith concentrations of 1×10-3%(in volume,the sa...The effects of NOx(in a ratio of NO∶NO2=9∶1) and SO2in cathode streamonthe performance of a single proton ex-change membrane fuel cell(PEMFC) were investigated.NOxwith concentrations of 1×10-3%(in volume,the same as fol-lows),1.4×10-2%and 1×10-3%could cause significant detri mental effects on the cell performance.However,nearly com-plete recovery of the cell performance could be observed after NOxwas shut off and purged with clean air.The electrochemicalmeasurements suggested that thei mpacts of NOxresulted mainlyfromthe superposition of the oxygen reduction reaction(ORR),NOand HNO2oxidation reactions,and the increased cathodic i mpedance.Trace SO2with concentrations of 5×10-6%,5×10-3%,2×10-4%and 3.2×10-4%influenced the cell muchseverer,which could be attributed toits strong adsorption onthesurface of Pt atoms.The cell performance could not be completely recovered after purged with clean air and cyclic voltammetry(CV) tests,due to the changes of electrochemical i mpedance spectroscopy(EIS) and electrochemical active surface(EAS) causedby surface state change after SO2exposure.展开更多
The electrolysis expansion of semigraphitic cathode in [K3AlF6/Na3AlF6]-AlF3-Al2O3 bath system was tested by self-made modified Rapoport apparatus. A mathematical model was introduced to discuss the effects of acR （c...The electrolysis expansion of semigraphitic cathode in [K3AlF6/Na3AlF6]-AlF3-Al2O3 bath system was tested by self-made modified Rapoport apparatus. A mathematical model was introduced to discuss the effects of acR （cryolite ratio） and βKR （elpasolite content divided by the total amount of elpasolite and sodium cryolite） on performance of cathode electrolysis expansion. The results show that K and Na （potassium and sodium） penetrate into the cathode together and have an obvious influence on the performance of cathode electrolysis expansion. The electrolysis expansion and K/Na penetration rate increase with the increase of αCR. When αCR=1.9 and βKR=0.5, the electrolysis expansion is the highest, which is 3.95%; and when αCR=I.4 and βKR=0.1, the electrolysis expansion is the lowest, which is 1.28%. But the effect offlKR is correlative with αCR. When αCR=1.6 and 1.9, with the increase of titan, the electrolysis expansion and K/Na penetration rate increase. However, when αCR=l.4, the electrolysis expansion and K/Na penetration rate firstly increase and then decrease with the increase of βKR.展开更多
The sodium expansion curves of semi-graphitic cathode measured with the improved Rapoport-Samoilenko apparatus. The and TiB2/C composite cathode with different TiB2 contents were mathematic model of the sodium expansi...The sodium expansion curves of semi-graphitic cathode measured with the improved Rapoport-Samoilenko apparatus. The and TiB2/C composite cathode with different TiB2 contents were mathematic model of the sodium expansion was deduced on the basis of the experimental results. The sodium expansion parameter （a） and penetration rate factor （Q）, were introduced into the model The model was validated with the experimental sodium expansion curves self-measured and reported. The results show that the variation tendency of the sodium expansion parameter （a） and penetration rate factor （Q） is consistent with that of the experimental curves. The model is capable of not only conveniently judging the cathode quality, but also favorably establishing a unified standard of the resistance to sodium penetration of cathode.展开更多
A potential 4.2 V cathode material LiVPO4F for lithium batteries was prepared by two-step reaction method based on a carbon-thermal reduction （CTR） process. Firstly, V2O5, NH4H2PO4 and acetylene black are reacted un...A potential 4.2 V cathode material LiVPO4F for lithium batteries was prepared by two-step reaction method based on a carbon-thermal reduction （CTR） process. Firstly, V2O5, NH4H2PO4 and acetylene black are reacted under an Ar atmosphere to yield VPO4. The transition-metal reduction is facilitated by the CTR based on C→CO transition. These CTR conditions favor stabilization of the vanadium as V^3＋ as well as leaving residual carbon, which is useful in the subsequent electrode processing. Secondly, VPO4 reacts with ElF to yield LiVPO4F product. The property of the LiVPO4F was investigated by X-ray diffractometry （XRD）, scanning electron microscopy （SEM） and electrochemical measurement. XRD studies show that LiVPO4F synthesized has triclinic structure（space group p I ）, isostructural with the naturally occurring mineral tavorite, EiFePO4-OH. SEM image exhibits that the particle size is about 2μm together with homogenous distribution. Electrochemical test shows that the initial discharge capacity of LiVPO4F powder is 119 mA·h/g at the rate of 0.2C with an average discharge voltage of 4.2V （vs Ei/Li^＋）, and the capacity retains 89 mA·h/g after 30 cycles.展开更多
To recover metal from copper slags,a new process involving two steps of oxidative desulfurization followed by smelting reduction was proposed in which one hazardous waste(waste cathode carbon)was used to treat another...To recover metal from copper slags,a new process involving two steps of oxidative desulfurization followed by smelting reduction was proposed in which one hazardous waste(waste cathode carbon)was used to treat another(copper slags).The waste cathode carbon is used not only as a reducing agent but also as a fluxing agent to decrease slag melting point.Upon holding for 60 min in air atmosphere first and then smelting with 14.4 wt%waste cathode carbon and 25 wt%CaO for 180 min in high purity Ar atmosphere at 1450℃,the recovery rates of Cu and Fe reach 95.89%and 94.64%,respectively,and meanwhile greater than 90%of the fluoride from waste cathode carbon is transferred into the final slag as CaF_(2) and Ca_(2)Si_(2)F_(2)O_(7),which makes the content of soluble F in the slag meet the national emission standard.Besides,the sulphur content in the obtained Fe-Cu alloy is low to 0.03 wt%.展开更多
TiB2/C cathode composites with various contents of TiB2 were prepared and their characterizations were observed and compared. The expansion of samples due to sodium and bath penetration was tested with a modified labo...TiB2/C cathode composites with various contents of TiB2 were prepared and their characterizations were observed and compared. The expansion of samples due to sodium and bath penetration was tested with a modified laboratory Rapoport apparatus and the appearances of the cut sections of specimens after electrolysis were studied. The results show that the mass of TiB2/C cathode composites with mass fraction of TiB2 less than 70% appreciably increases, but that of the composites with mass fraction of TiB2 more than 70% decreases slightly after being baked. The resistance to sodium and bath penetration of TiB2/C cathode composites increases with the increase of TiB2 content, especially in the composites with high TiB2 content. TiB2/C cathode composites have high resistance to the penetration of sodium and bath as well as good wettability by molten aluminum, and keep integrality and have little change of appearance after electrolysis, which indicates that TiB2/C cathode composites can be used as inert wettable cathode for aluminum electrolysis.展开更多
This work presents a method to solve the weak solubility of zinc chloride(ZnCl_2) in the ethanol by adding some reasonable water into an ethanol electrolyte containing ZnCl_2 and myristic acid(CH_3(CH_2)_(12)COOH).A r...This work presents a method to solve the weak solubility of zinc chloride(ZnCl_2) in the ethanol by adding some reasonable water into an ethanol electrolyte containing ZnCl_2 and myristic acid(CH_3(CH_2)_(12)COOH).A rapid one-step electrodeposition process was developed to fabricate anodic(2.5 min) and cathodic(40 s) superhydrophobic surfaces of copper substrate(contact angle more than 150°) in an aqueous ethanol electrolyte.Morphology,composition,chemical structure and superhydrophobicity of these superhydrophobic surfaces were investigated by SEM,FTIR,XRD,and contact angle measurement,respectively.The results indicate that water ratio of the electrolyte can reduce the required deposition time,superhydrophobic surface needs over 30 min with anhydrous electrolyte,while it needs only 2.5 min with electrolyte including 10 mL water,and the maximum contact angle of anodic surface is 166° and that of the cathodic surface is 168°.Two copper electrode surfaces have different reactions in the process of electrodeposition time,and the anodic copper surface covers copper myristate(Cu[CH_3(CH_2)_(12)COO]_2) and cupric chloride(CuCl);while,zinc myristate(Zn[CH_3(CH_2)_(12)COO]_2) and pure zinc(Zn) appear on the cathodic surface.展开更多
LiNi0. 45 Co0. 10 Mn0. 4sO2 was synthesized from Li2CO3 and a triple oxide of nickel, cobalt and manganese at 950 ℃ in air. The structures and characteristics of LiNi0. 45 Co0.10 Mn0. 45 O2, LiCoO2 and LiMn2 O4 were ...LiNi0. 45 Co0. 10 Mn0. 4sO2 was synthesized from Li2CO3 and a triple oxide of nickel, cobalt and manganese at 950 ℃ in air. The structures and characteristics of LiNi0. 45 Co0.10 Mn0. 45 O2, LiCoO2 and LiMn2 O4 were investigated by XRD, SEM and electrochemical measurements. The results show that LiNi0.4s Co0.10 Mn0. 45 O2 has a layered structure with hexagonal lattice. The commercial LicoO2 has sphere-like appearance and smooth surfaces, while the LiMn2 O4 and LiNi0.45 Co0. 10 Mn0. 45 O2 consist of cornered and uneven particles. LiNi0. 45 Co0.10 Mn0. 45 O2 has a large disLiMn2 O4 and LiCoO2, respectively. LiCoO2 and LiMn2 O4 have higher discharge voltage and better rate-capability than LiNi0. 45Co0.10 Mn0. 45 O2. All the three cathodes have excellent cycling performance with capacity retention of above 89.3 % at the 250th cycle. Batteries with LiMn2 O4 or LiNi0.45 Co0.10 Mn0. 45 O2 cathodes show better safety performance under abusive conditions than those with LiCoO2 cathodes.展开更多
Li2FeSiO4 is deemed to be a potential candidate for large-scale applications because of its abundance,low cost and high safety,etc.Unfortunately,its low conductivity,resulting in poor rate performance,has become a mai...Li2FeSiO4 is deemed to be a potential candidate for large-scale applications because of its abundance,low cost and high safety,etc.Unfortunately,its low conductivity,resulting in poor rate performance,has become a main obstacle to its applications in power battery and energy storage system.In this work,C-Ag coated Li2FeSiO4 is introduced to improve the innate electronic conductivity and Li-ion diffusion ability.The results demonstrate that Li2FeSiO4/C/Ag composite exhibits better electrochemical performance.It possesses a specific discharge capacity of 152,121,108 mA.h/g at 0.2C,5C and 10C,respectively.At the same time,the Li2FeSiO4/C/Ag composite shows good cycle stability and a capacity retention ratio of 97.9%after 100 cycles at 1C.展开更多
LiNi_(0.5)Mn_(1.5)O_(4)was prepared under various conditions by one-step solid-state reaction in air and its properties were investigated by X-ray diffractormetry(XRD),scanning electron microscopy(SEM)and electrochemi...LiNi_(0.5)Mn_(1.5)O_(4)was prepared under various conditions by one-step solid-state reaction in air and its properties were investigated by X-ray diffractormetry(XRD),scanning electron microscopy(SEM)and electrochemical measurement.XRD patterns show that LiNi_(0.5)Mn_(1.5)O_(4)synthesized under various conditions has cubic spinel structure.SEM images exhibit that the particle size increases with increasing calcination temperature and time.Electro chemical test shows that the LiNi_(0.5)Mn_(1.5)O_(4)calcined at 700℃for 24 h delivers up to 143 mA·h/g,and the capacity retains 132 mA·h/g after 30 cycles.展开更多
High dispersed carbon black was applied for LiFePO4 cathodes as conductive agent.Nano-conductive carbon agent was pre-dispersed with poly acrylic acid(PAA) as dispersant in organic N-methyl-pyrrolidone(NMP) solvent sy...High dispersed carbon black was applied for LiFePO4 cathodes as conductive agent.Nano-conductive carbon agent was pre-dispersed with poly acrylic acid(PAA) as dispersant in organic N-methyl-pyrrolidone(NMP) solvent system.The dispersion property of nano-conductive carbon agent was evaluated using particle size distribution measurements,scanning electron microscopy(SEM) and transmission electron microscope(TEM).LiFePO4 cathode with as-received nano-conductive carbon agent(SP) and LiFePO4 cathode with pre-dispersed nano-conductive carbon agent(SP-PAA) were examined by scanning electron microscopy(SEM),cyclic voltammetry(CV),electrochemical impendence spectroscopy(EIS) and charge/discharge cycling performance.Results show that the dispersion property of carbon black is improved by using PAA as the dispersant.The LiFePO4 cathodes with SP-PAA exhibit improved rate behaviors(4C,135.1 mAh/g) and cycle performance(95%,200 cycles) compared to LiFePO4 cathodes with SP(4C,103.9 mAh/g and 83%,200 cycles).Because pre-dispersed carbon black(SP-PAA) is dispersed homogeneously in the dried composite electrode to form a more uniform conductive network between the active material particles,electrochemical performances of the LiFePO4 cathodes are improved.展开更多
Binary carbon mixtures, carbon black ECP 600JD(ECP) combined with vapor grown carbon fiber(VGCF) or carbon nanotube(CNT), or graphene(Gr) in different mass ratios, are investigated as the conductive additives for the ...Binary carbon mixtures, carbon black ECP 600JD(ECP) combined with vapor grown carbon fiber(VGCF) or carbon nanotube(CNT), or graphene(Gr) in different mass ratios, are investigated as the conductive additives for the cathode material polyoxomolybadate Na_3[AlMo_6O_(24)H_6](NAM). Field emission scanning electron microscopy and energy dispersive X-ray spectroscopy show that the surfaces of NAM particles are covered homogeneously with the binary conductive additive mixtures except the combination of ECP and CNT. The optimum combination is the mixture of ECP and VGCF, which shows higher discharge capacity than the combinations of ECP and CNT or Gr. Initial discharge capacities of 364, 339, and 291 m A·h/g are obtained by the combination of ECP and VGCF in the mass ratios of 2:1, 1:1, and 1:2, respectively. The results of electrochemical impedance spectra and 4-pin probe measurements demonstrate that the combination of ECP and VGCF exhibits the highest electrical conductivity for the electrode.展开更多
基金supported by National Key R&D Program of China(2021YFB4001401)National Natural Science Foundation of China(52272190,22178023).
文摘Solid oxide electrolysis cells(SOECs)can effectively convert CO_(2)into high value-added CO fuel.In this paper,Sc-doped Sr_(2)Fe_(1.5)Mo_(0.3)Sc_(0.2)O_(6−δ)(SFMSc)perovskite oxide material is synthesized via solid-phase method as the cathode for CO_(2)electrolysis by SOECs.XRD confirms that SFMSc exhibits a stable cubic phase crystal structure.The experimental results of TPD,TG,EPR,CO_(2)-TPD further demonstrate that Sc-doping increases the concentration of oxygen vacancy in the material and the chemical adsorption capacity of CO_(2)molecules.Electrochemical tests reveal that SFMSc single cell achieves a current density of 2.26 A/cm^(2) and a lower polarization impedance of 0.32Ω·cm^(2) at 800°C under the applied voltage of 1.8 V.And no significant performance attenuation or carbon deposition is observed after 80 h continuous long-term stability test.This study provides a favorable support for the development of SOEC cathode materials with good electro-catalytic performance and stability.
基金supported by the Significant Science and Technology Project in Xiamen(Future Industry Field)(Grant No.3502Z20231057).
文摘Lithium nickel oxide(Li_(2)NiO_(2)),as a sacrificial cathode prelithiation additive,has been used to compensate for the lithium loss for improving the lifespan of lithium-ion batteries(LIBs).However,high-cost Li_(2)NiO_(2)suffers from inferior delithiation kinetics during the first cycle.Herein,we investigated the effects of the cost-effective copper substituted Li_(2)Ni_(1-x)Cu_(x)O_(2)(x=0,0.2,0.3,0.5,0.7)synthesized by a high-temperature solid-phase method on the structure,morphology,electrochemical performance of graphite‖LiFePO_(4)battery.The X-ray diffraction(XRD)refinement result demonstrated that Cu substitution strategy could be favorable for eliminating the NiO_(x)impurity phase and weakening Li-O bond.Analysis on density of states(DOS)indicates that Cu substitution is good for enhancing the electronic conductivity,as well as reducing the delithi-ation voltage polarization confirmed by electrochemical characterizations.Therefore,the optimal Li_(2)Ni_(0.7)Cu_(0.3)O_(2)delivered a high delithiation capacity of 437 mAh·g^(-1),around 8%above that of the pristine Li_(2)NiO_(2).Furthermore,a graphite‖LiFePO_(4)pouch cell with a nominal capacity of 3000 mAh demonstrated a notably improved reversible capacity,energy density and cycle life through introducing 2 wt%Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive,delivering a 6.2 mAh·g^(-1)higher initial discharge capacity and achieving around 5%improvement in capacity retentnion at 0.5P over 1000 cycles.Additionally,the post-mortem analyses testified that the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive could suppress solid electrolyte interphase(SEI)decomposition and homogenize the Li distribution,which benefits to stabilizing interface between graphite and electrolyte,and alleviating dendritic Li plating.In conclusion,the Li_(2)Ni_(0.7)Cu_(0.3)O_(2)additive may offer advantages such as lower cost,lower delithiation voltage and higher prelithiation capacity compared with Li_(2)NiO_(2),making it a promising candidate of cathode prelithiation additive for next-generation LIBs.
文摘This study focuses on using a green reagent scheme of methanesulfonic acid (MSA) and citric acid (CA) to extract valuable metals from the cathodes, aiming to minimize environmental impact during the recycling process. Leaching studies on LiCoO_(2) identified optimal conditions as follows: 2.4 mol/L MSA, 1.6 mol/L CA, S/L ratio of 80 g/L, leaching temperature of 90oC and leaching time of 6 h. The maximum Co and Li extraction achieved was 92% and 85%, respectively. LiCoO_(2) dissolution in MSA-CA leaching solution is highly impacted by temperature;Avrami equation showed a good fitting for the leaching data. The experimental activation energy of Co and Li was 50.98 kJ/mol and 50.55 kJ/mol, respectively, indicating that it is a chemical reaction-controlled process. Furthermore, cobalt was efficiently recovered from the leachate using oxalic acid, achieving a precipitation efficiency of 99.91% and a high-purity cobalt oxalate product (99.85 wt.%). In the MSA-CA leaching solution, MSA served as a lixiviant, while CA played a key role in reducing Co in LiCoO_(2). The overall organic acid leaching methodology presents an attractive option due to its reduced environmental impact.
基金Project(23JCYBJC01870)supported by the Natural Science Foundation of Tianjin,ChinaProject(U22A20119)supported by the National Natural Science Foundation of China。
文摘As a cathode material for thermal batteries,NiS_(2)has a high theoretical capacity but low thermal stability.Besides,the poor formability of NiS_(2)powders also restricts the cathode performance of thermal batteries.In this paper,the novel NiS_(2)/SiO_(2)composite material was developed by high temperature vulcanization to improve the thermal stability formability of NiS_(2).The good filling and lubrication of spherical SiO_(2)can improve the thermal conductivity of NiS_(2)electrode.The discharge test shows that the NiS_(2)/SiO_(2)cathode has a stable discharge voltage at a current density of 200 mA/cm^(2),and the activation time is shortened by nearly 20%compared with the NiS_(2)cathode.In addition,due to the favorable thermal insulation protection of SiO_(2),the initial decomposition temperature of NiS_(2)is increased by 30℃after the addition of SiO_(2).The incorporation of SiO_(2)not only effectively improves the thermal stability and electrochemical properties of NiS_(2),but also improves the cold pressing forming performance of the NiS_(2)powder.Therefore,the novel NiS_(2)/SiO_(2)composite material is more suitable for thermal batteries with high stability and fast response,which is of great significance for improving the maneuverability and quality reliability of weapons and equipment.
基金the financial support from the National Natural Science Foundation of China (No. 21925403)the Excellent Research Program of Nanjing University (Grant No. ZYJH004)。
文摘Developing in situ spectroelectrochemistry methods,which can provide detailed information about species trans-formation during electrochemical reactions,is very important for studying electrode reaction mechanisms and improving battery performance.Studying real-time changes in the surface of electrode materials during normal operation can be an effective way to assess and optimize the practical performance of electrode materials,thus,in situ and in operando characterization techniques are particularly important.However,batteries are hard to be studied by in situ characterization measurements due to their hermetically sealed shells,and there is still much room for battery characterizations.In this work,a specially designed battery based on the structure of coin cells,whose upper cover was transparent,was constructed.With such a device,acquisition of diffuse reflectance spectra of electrode materials during charging and discharging was realized.This not only provided a simple measurement accessory for diffuse reflectance spectroscopy(DRS),but also complemented in situ characterization techniques for batteries.Taking commonly used cathode materials in lithium-ion batteries(LIBs),including LiFePO_(4)(LFP),NCM811 and LiCoO_(2)(LCO)as examples,we managed tofind out the response relationships of different electrode materials to visible light of different wavelengths under ordinary reflectance illumination conditions.Heterogeneity of different cathode ma-terials on interaction relationships with the lights of different wavelengths was also revealed.This work demonstrated the capability of guiding wavelength selection for different materials and assessing electrochemical performances of in situ diffuse reflectance spectroelectrochemistry.By combining electrochemistry with diffuse reflectance spectroscopy,this work made an effective complementary for spectroelectrochemistry.
基金National Key R&D Program of China(2022YFB3807700)National Natural Science Foundation of China(22133005,22103093)+4 种基金Science and Technology Commission of Shanghai Municipality(21ZR1472900,22ZR1471600,23ZR1472600)Youth Innovation Promotion Association CAS(2022251)Shanghai Super Post-Doctor Incentive Program(2022665)China Postdoctoral Science Foundation(2023M733621)Shanghai Explorer Program(Batch I)(23TS1401500)。
文摘Sodium-ion batteries are economical and environmentally sustainable energy storage batteries.Among them,β-NaMnO_(2),a promising sodium-ion cathode material,is a manganese-based oxide with a corrugated laminar structure,which has attracted significant attention due to its structural robustness and relatively high specific capacity.However,it has short cycle life and poor rate capability.To address these issues,Ti atoms,known for enhancing structural stability,and Cu atoms,which facilitate desodiation,were doped intoβ-NaMnO_(2) by first-principles calculation and crystal orbital Hamilton population(COHP)analysis.β-NaMn_(0.8)Ti_(0.1)Cu_(0.1)O_(2) exhibits a notable increase in reversible specific capacity and remarkable rate properties.Operating at a current density of 0.2C(1C=219 mA·g^(–1))and within a voltage range of 1.8–4.0 V,the modified material delivers an initial discharge capacity of 132 mAh·g^(–1).After charge/discharge testing at current densities of 0.2C,0.5C,1C,3C,and 0.2C,the material still maintains a capacity of 110 mA h·g^(–1).The doping of Ti atoms slows down the changes in the crystal structure,resulting in only minimal variation in the lattice constant c/a during the desodiation process.Mn and Cu engage in reversible redox reactions at voltages below 3.0 V and around 3.5 V,respectively.The extended plateau observed in the discharge curve below 3.0 V signifies that Mn significantly contributes to the overall battery capacity.This study provides insights into modifyingβ-NaMnO_(2) as a cathode material,offering experimental evidence and theoretical guidance for enhancing battery performance in Na-ion batteries.
基金Project(2023JJ40759)supported by the Natural Science Foundation of Hunan Province,China。
文摘The irreversible phase transition and interface side reactions during the cycling process severely limit the large scale application of nickel-rich layered oxides Li[Ni_(x)Co_(y)Mn_(1−x−y)]O_(2)(NCM,x>0.8).Herein,we have designed LiNi_(0.8)Co_(0.1)Mn 0.1 O_(2)cathodes modified by Nb/Al co-doping and LiNbO_(3)/LiAlO_(2)composite coating.Detailed characterization reveals that Nb/Al co-doping can stabilize the crystal structure of the cathodes and expand the layer spacing of the layered lattice,thereby increasing the diffusion rate and reversibility of Li^(+).And the composite coatings can improve the electrochemical kinetic and inhibit the erosion of acidic substances by hindering direct contact between the cathodes and electrolyte.As a result,the Ni-rich cathodes with dual modification can still exhibit a higher capacity of 184.02 mA·h/g after 100 cycles with a capacity retention of up to 98.1%,and can still release a capacity of 161.6 mA·h/g at a high rate of 7 C,meanwhile,it shows excellent thermal stability compared to bare NCM.This work provides a new perspective for enhancing electrochemical properties of cathodes through integrated strategies.
文摘The effects of NOx(in a ratio of NO∶NO2=9∶1) and SO2in cathode streamonthe performance of a single proton ex-change membrane fuel cell(PEMFC) were investigated.NOxwith concentrations of 1×10-3%(in volume,the same as fol-lows),1.4×10-2%and 1×10-3%could cause significant detri mental effects on the cell performance.However,nearly com-plete recovery of the cell performance could be observed after NOxwas shut off and purged with clean air.The electrochemicalmeasurements suggested that thei mpacts of NOxresulted mainlyfromthe superposition of the oxygen reduction reaction(ORR),NOand HNO2oxidation reactions,and the increased cathodic i mpedance.Trace SO2with concentrations of 5×10-6%,5×10-3%,2×10-4%and 3.2×10-4%influenced the cell muchseverer,which could be attributed toits strong adsorption onthesurface of Pt atoms.The cell performance could not be completely recovered after purged with clean air and cyclic voltammetry(CV) tests,due to the changes of electrochemical i mpedance spectroscopy(EIS) and electrochemical active surface(EAS) causedby surface state change after SO2exposure.
基金Project (2005CB623703) supported by the Major State Basic Research and Development Program of ChinaProject (2008AA030502) supported by the National High-Tech Research and Development Program of China
文摘The electrolysis expansion of semigraphitic cathode in [K3AlF6/Na3AlF6]-AlF3-Al2O3 bath system was tested by self-made modified Rapoport apparatus. A mathematical model was introduced to discuss the effects of acR （cryolite ratio） and βKR （elpasolite content divided by the total amount of elpasolite and sodium cryolite） on performance of cathode electrolysis expansion. The results show that K and Na （potassium and sodium） penetrate into the cathode together and have an obvious influence on the performance of cathode electrolysis expansion. The electrolysis expansion and K/Na penetration rate increase with the increase of αCR. When αCR=1.9 and βKR=0.5, the electrolysis expansion is the highest, which is 3.95%; and when αCR=I.4 and βKR=0.1, the electrolysis expansion is the lowest, which is 1.28%. But the effect offlKR is correlative with αCR. When αCR=1.6 and 1.9, with the increase of titan, the electrolysis expansion and K/Na penetration rate increase. However, when αCR=l.4, the electrolysis expansion and K/Na penetration rate firstly increase and then decrease with the increase of βKR.
基金Project(2005CB623703) supported by the Major State Basic Research and Development Program of ChinaProject(2008AA030502) supported by the National High-Tech Research and Development Program of ChinaProject(GUIKEJI0639032) supported by the Science Fund Project of Guangxi Province, China
文摘The sodium expansion curves of semi-graphitic cathode measured with the improved Rapoport-Samoilenko apparatus. The and TiB2/C composite cathode with different TiB2 contents were mathematic model of the sodium expansion was deduced on the basis of the experimental results. The sodium expansion parameter （a） and penetration rate factor （Q）, were introduced into the model The model was validated with the experimental sodium expansion curves self-measured and reported. The results show that the variation tendency of the sodium expansion parameter （a） and penetration rate factor （Q） is consistent with that of the experimental curves. The model is capable of not only conveniently judging the cathode quality, but also favorably establishing a unified standard of the resistance to sodium penetration of cathode.
基金Project(50302016) supported by the National Natural Science Foundation of China
文摘A potential 4.2 V cathode material LiVPO4F for lithium batteries was prepared by two-step reaction method based on a carbon-thermal reduction （CTR） process. Firstly, V2O5, NH4H2PO4 and acetylene black are reacted under an Ar atmosphere to yield VPO4. The transition-metal reduction is facilitated by the CTR based on C→CO transition. These CTR conditions favor stabilization of the vanadium as V^3＋ as well as leaving residual carbon, which is useful in the subsequent electrode processing. Secondly, VPO4 reacts with ElF to yield LiVPO4F product. The property of the LiVPO4F was investigated by X-ray diffractometry （XRD）, scanning electron microscopy （SEM） and electrochemical measurement. XRD studies show that LiVPO4F synthesized has triclinic structure（space group p I ）, isostructural with the naturally occurring mineral tavorite, EiFePO4-OH. SEM image exhibits that the particle size is about 2μm together with homogenous distribution. Electrochemical test shows that the initial discharge capacity of LiVPO4F powder is 119 mA·h/g at the rate of 0.2C with an average discharge voltage of 4.2V （vs Ei/Li^＋）, and the capacity retains 89 mA·h/g after 30 cycles.
基金Project(U1602272)supported by the National Natural Science Foundation of China。
文摘To recover metal from copper slags,a new process involving two steps of oxidative desulfurization followed by smelting reduction was proposed in which one hazardous waste(waste cathode carbon)was used to treat another(copper slags).The waste cathode carbon is used not only as a reducing agent but also as a fluxing agent to decrease slag melting point.Upon holding for 60 min in air atmosphere first and then smelting with 14.4 wt%waste cathode carbon and 25 wt%CaO for 180 min in high purity Ar atmosphere at 1450℃,the recovery rates of Cu and Fe reach 95.89%and 94.64%,respectively,and meanwhile greater than 90%of the fluoride from waste cathode carbon is transferred into the final slag as CaF_(2) and Ca_(2)Si_(2)F_(2)O_(7),which makes the content of soluble F in the slag meet the national emission standard.Besides,the sulphur content in the obtained Fe-Cu alloy is low to 0.03 wt%.
文摘TiB2/C cathode composites with various contents of TiB2 were prepared and their characterizations were observed and compared. The expansion of samples due to sodium and bath penetration was tested with a modified laboratory Rapoport apparatus and the appearances of the cut sections of specimens after electrolysis were studied. The results show that the mass of TiB2/C cathode composites with mass fraction of TiB2 less than 70% appreciably increases, but that of the composites with mass fraction of TiB2 more than 70% decreases slightly after being baked. The resistance to sodium and bath penetration of TiB2/C cathode composites increases with the increase of TiB2 content, especially in the composites with high TiB2 content. TiB2/C cathode composites have high resistance to the penetration of sodium and bath as well as good wettability by molten aluminum, and keep integrality and have little change of appearance after electrolysis, which indicates that TiB2/C cathode composites can be used as inert wettable cathode for aluminum electrolysis.
基金Projects(11304243,11102164)supported by the National Natural Science Foundation of ChinaProject(2014JQ1039)supported by the Natural Science Foundation of Shannxi Province,China+3 种基金Project(12JK0966)supported by the Shaanxi Provincial Education Department,ChinaProject(2013QDJ037)supported by the Xi’an University of Science and Technology Dr Scientific Research Fund,ChinaProject(3102016ZY027)supported by the Fundamental Research Funds for the Central Universities of ChinaProject(13GH014602)supported by the Program of New Staff and Research Area Project of NPU,China
文摘This work presents a method to solve the weak solubility of zinc chloride(ZnCl_2) in the ethanol by adding some reasonable water into an ethanol electrolyte containing ZnCl_2 and myristic acid(CH_3(CH_2)_(12)COOH).A rapid one-step electrodeposition process was developed to fabricate anodic(2.5 min) and cathodic(40 s) superhydrophobic surfaces of copper substrate(contact angle more than 150°) in an aqueous ethanol electrolyte.Morphology,composition,chemical structure and superhydrophobicity of these superhydrophobic surfaces were investigated by SEM,FTIR,XRD,and contact angle measurement,respectively.The results indicate that water ratio of the electrolyte can reduce the required deposition time,superhydrophobic surface needs over 30 min with anhydrous electrolyte,while it needs only 2.5 min with electrolyte including 10 mL water,and the maximum contact angle of anodic surface is 166° and that of the cathodic surface is 168°.Two copper electrode surfaces have different reactions in the process of electrodeposition time,and the anodic copper surface covers copper myristate(Cu[CH_3(CH_2)_(12)COO]_2) and cupric chloride(CuCl);while,zinc myristate(Zn[CH_3(CH_2)_(12)COO]_2) and pure zinc(Zn) appear on the cathodic surface.
基金Project(50302016) supported by the National Natural Science Foundation of China Project(2005037698) supported by the Postdoctoral Science Foundation of China
文摘LiNi0. 45 Co0. 10 Mn0. 4sO2 was synthesized from Li2CO3 and a triple oxide of nickel, cobalt and manganese at 950 ℃ in air. The structures and characteristics of LiNi0. 45 Co0.10 Mn0. 45 O2, LiCoO2 and LiMn2 O4 were investigated by XRD, SEM and electrochemical measurements. The results show that LiNi0.4s Co0.10 Mn0. 45 O2 has a layered structure with hexagonal lattice. The commercial LicoO2 has sphere-like appearance and smooth surfaces, while the LiMn2 O4 and LiNi0.45 Co0. 10 Mn0. 45 O2 consist of cornered and uneven particles. LiNi0. 45 Co0.10 Mn0. 45 O2 has a large disLiMn2 O4 and LiCoO2, respectively. LiCoO2 and LiMn2 O4 have higher discharge voltage and better rate-capability than LiNi0. 45Co0.10 Mn0. 45 O2. All the three cathodes have excellent cycling performance with capacity retention of above 89.3 % at the 250th cycle. Batteries with LiMn2 O4 or LiNi0.45 Co0.10 Mn0. 45 O2 cathodes show better safety performance under abusive conditions than those with LiCoO2 cathodes.
基金Project(21771062)supported by the National Natural Science Foundation of ChinaProject(2016JJ2092)supported by the Hunan Provincial Natural Science Foundation,ChinaProject(2019013)supported by the Open Project Program of Key Laboratory of Preparation and Application of Environmental Friendly Materials,Ministry of Education,Jilin Normal University,China
文摘Li2FeSiO4 is deemed to be a potential candidate for large-scale applications because of its abundance,low cost and high safety,etc.Unfortunately,its low conductivity,resulting in poor rate performance,has become a main obstacle to its applications in power battery and energy storage system.In this work,C-Ag coated Li2FeSiO4 is introduced to improve the innate electronic conductivity and Li-ion diffusion ability.The results demonstrate that Li2FeSiO4/C/Ag composite exhibits better electrochemical performance.It possesses a specific discharge capacity of 152,121,108 mA.h/g at 0.2C,5C and 10C,respectively.At the same time,the Li2FeSiO4/C/Ag composite shows good cycle stability and a capacity retention ratio of 97.9%after 100 cycles at 1C.
基金Project(76600)supported by Postdoctoral Science Foundation of Central South University
文摘LiNi_(0.5)Mn_(1.5)O_(4)was prepared under various conditions by one-step solid-state reaction in air and its properties were investigated by X-ray diffractormetry(XRD),scanning electron microscopy(SEM)and electrochemical measurement.XRD patterns show that LiNi_(0.5)Mn_(1.5)O_(4)synthesized under various conditions has cubic spinel structure.SEM images exhibit that the particle size increases with increasing calcination temperature and time.Electro chemical test shows that the LiNi_(0.5)Mn_(1.5)O_(4)calcined at 700℃for 24 h delivers up to 143 mA·h/g,and the capacity retains 132 mA·h/g after 30 cycles.
基金Project(51204211) supported by the National Natural Science Foundation of ChinaProject(2012M521543) supported by the China Postdoctoral Science Foundation
文摘High dispersed carbon black was applied for LiFePO4 cathodes as conductive agent.Nano-conductive carbon agent was pre-dispersed with poly acrylic acid(PAA) as dispersant in organic N-methyl-pyrrolidone(NMP) solvent system.The dispersion property of nano-conductive carbon agent was evaluated using particle size distribution measurements,scanning electron microscopy(SEM) and transmission electron microscope(TEM).LiFePO4 cathode with as-received nano-conductive carbon agent(SP) and LiFePO4 cathode with pre-dispersed nano-conductive carbon agent(SP-PAA) were examined by scanning electron microscopy(SEM),cyclic voltammetry(CV),electrochemical impendence spectroscopy(EIS) and charge/discharge cycling performance.Results show that the dispersion property of carbon black is improved by using PAA as the dispersant.The LiFePO4 cathodes with SP-PAA exhibit improved rate behaviors(4C,135.1 mAh/g) and cycle performance(95%,200 cycles) compared to LiFePO4 cathodes with SP(4C,103.9 mAh/g and 83%,200 cycles).Because pre-dispersed carbon black(SP-PAA) is dispersed homogeneously in the dried composite electrode to form a more uniform conductive network between the active material particles,electrochemical performances of the LiFePO4 cathodes are improved.
文摘Binary carbon mixtures, carbon black ECP 600JD(ECP) combined with vapor grown carbon fiber(VGCF) or carbon nanotube(CNT), or graphene(Gr) in different mass ratios, are investigated as the conductive additives for the cathode material polyoxomolybadate Na_3[AlMo_6O_(24)H_6](NAM). Field emission scanning electron microscopy and energy dispersive X-ray spectroscopy show that the surfaces of NAM particles are covered homogeneously with the binary conductive additive mixtures except the combination of ECP and CNT. The optimum combination is the mixture of ECP and VGCF, which shows higher discharge capacity than the combinations of ECP and CNT or Gr. Initial discharge capacities of 364, 339, and 291 m A·h/g are obtained by the combination of ECP and VGCF in the mass ratios of 2:1, 1:1, and 1:2, respectively. The results of electrochemical impedance spectra and 4-pin probe measurements demonstrate that the combination of ECP and VGCF exhibits the highest electrical conductivity for the electrode.
