The La-Mg-Ni-based A2B7-type La0.5Mg0.2Ni3.3Co0.2Six （x=0-0.2） electrode alloys were prepared by casting and annealing. The influences of the additional silicon and the annealing treatment on the structure and elect...The La-Mg-Ni-based A2B7-type La0.5Mg0.2Ni3.3Co0.2Six （x=0-0.2） electrode alloys were prepared by casting and annealing. The influences of the additional silicon and the annealing treatment on the structure and electrochemical performances of the alloys were investigated systemically. Both of the analyses of XRD and SEM reveal that the as-cast and annealed alloys are of a multiphase structure, involving two main phases （La, Mg）2Ni7 and LaNi5 as well as one minor phase LaNi3. The addition of Si and annealing treatment bring on an evident change in the phase abundances and cell parameters of （La, Mg）2Ni7 and LaNi5 phase for the alloy without altering its phase structure. The phase abundances decrease from 74.3% （x=0） to 57.8% （x=0.2） for the （La, Mg）2Ni7 phase, and those of LaNi5 phase increase from 20.2% （x^0） to 37.3% （x=0.2）. As for the electrochemical measurements, adding Si and performing annealing treatment have engendered obvious impacts. The cycle stability of the alloys is improved dramatically, being enhanced from 80.3% to 93.7% for the as-annealed （950 ℃） alloys with Si content increasing from 0 to 0.2. However, the discharge capacity is reduced by adding Si, from 399.4 to 345.3 mA.h/g as the Si content increases from 0 to 0.2. Furthermore, such addition makes the electrochemical kinetic properties of the alloy electrodes first increase and then decrease. Also, it is found that the overall electrochemical properties of the alloys first augment and then fall with the annealing temperature rising.展开更多
A LiFePO4/（C＋Fe2P） composite cathode material was prepared by a sol-gel method using Fe（NO3）3.9H20, LiAc·H2O）, NHaH2PO4 and citric acid as raw materials, and the physical properties and electrochemical perf...A LiFePO4/（C＋Fe2P） composite cathode material was prepared by a sol-gel method using Fe（NO3）3.9H20, LiAc·H2O）, NHaH2PO4 and citric acid as raw materials, and the physical properties and electrochemical performance of the composite cathode material were investigated by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and electrochemical tests. The Fe2P content, morphology and electrochemical performance of LiFePOa/（C＋Fe2P） composite depend on the calcination temperature. The optimized LiFePO4/（C＋FeeP） composite is prepared at 650 ~C and the optimized composite exhibits sphere-like morphology with porous structure and Fe2P content of about 3.2% （mass fraction）. The discharge capacity of the optimized LiFePO4/（C＋FeRP） at 0.1C is 156 and 161 mA.h/g at 25 and 55 ℃, respectively, and the corresponding capacity retentions are 96% after 30 cycles; while the capacity at 1C is 142 and 149 mA.h/g at 25 and 55 ℃, respectively, and the capacity still remains 135 and 142 mA-h/g after 30 cycles at 25 and 55℃, respectively.展开更多
Lithium(Li)-rich manganese(Mn)-based cathode Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2)(LRNCM)has attracted considerable attention owing to its high specific discharge capacity and low cost.However,unsatisfactory cycle ...Lithium(Li)-rich manganese(Mn)-based cathode Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2)(LRNCM)has attracted considerable attention owing to its high specific discharge capacity and low cost.However,unsatisfactory cycle performance and poor rate property hinder its large-scale application.The fast ionic conductor has been widely used as the cathode coating material because of its superior stability and excellent lithium-ion conductivity rate.In this study,Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2) is modified by using Li_(1.4)Al_(0.4)Ti_(1.6)(PO_(4))_(3)(LATP)ionic conductor.The electrochemical test results show that the discharge capacity of the resulting LRNCM@LATP1 sample is 198 mA·h/g after 100 cycles at 0.2C,with a capacity retention of 81%.Compared with the uncoated pristine LRNCM(188.4 m A·h/g and 76%),LRNCM after the LATP modification shows superior cycle performance.Moreover,the lithium-ion diffusion coefficient D_(Li+)is a crucial factor affecting the rate performance,and the D_(Li+)of the LRNCM material is improved from 4.94×10^(-13) to 5.68×10^(-12)cm^(2)/s after modification.The specific capacity of LRNCM@LATP1 reaches 102.5 mA·h/g at 5C,with an improved rate performance.Thus,the modification layer can considerably enhance the electrochemical performance of LRNCM.展开更多
Li4Ti5O12/C composite materials were synthesized by two-step solid state reaction method with glucose, sucrose, and starch as carbon sources, respectively. The effects of carbon sources on the structure, morphology, a...Li4Ti5O12/C composite materials were synthesized by two-step solid state reaction method with glucose, sucrose, and starch as carbon sources, respectively. The effects of carbon sources on the structure, morphology, and electrochemical performance of Li4Ti5O12/C composite materials were investigated by SEM, XRD and electrochemical tests. The results indicate that carbon sources have almost no effect on the structure of Li4Ti5O12/C composite materials. The initial discharge capacities of the Li4Ti1O12/C composite materials are slightly lower than those of as-synthesized Li4Ti5O12. However, Li4Ti5O12/C composite materials show better electrochemical rate performance than the as-synthesized Li4Ti5O12. The capacity retention （79%） of the Li4Ti5O12/C composite materials with starch as carbon source, is higher than that of Li4Ti5O12/C composite materials with glucose and sucrose as carbon source at current rate of 2.0C.展开更多
LiFePO4 was prepared by heating the pre-decomposed precursor mixtures sealed in vacuum quartz-tube. Three kinds of cooling modes including nature cooling, air quenching, and water quenching were applied to comparing t...LiFePO4 was prepared by heating the pre-decomposed precursor mixtures sealed in vacuum quartz-tube. Three kinds of cooling modes including nature cooling, air quenching, and water quenching were applied to comparing the effects of cooling modes on the microstructure and electrochemical characteristics of the material. The results indicate that the water quenching mode can control overgrowth of the grain size of final product and improve its electrochemical performance compared with nature cooling mode and air quenching mode. The sample synthesized by using water quenching mode is of the highest reversible discharge specific capacity and the best cyclic electrochemical performance, demonstrating the first discharge capacity of 138.1 mA·h/g at 0.1C rate and the total loss of capacity of 3.11% after 20 cycles.展开更多
A low-cost 1D cobalt-based coordination polymer(CP)[Co(BGPD)(DMSO)_(2)(H_(2)O)_(2)](Co-BD;H2BGPD=N,N'-bis(glycinyl)pyromellitic diimide;DMSO=dimethyl sulfoxide)was synthesized by a simple method,and its crystal st...A low-cost 1D cobalt-based coordination polymer(CP)[Co(BGPD)(DMSO)_(2)(H_(2)O)_(2)](Co-BD;H2BGPD=N,N'-bis(glycinyl)pyromellitic diimide;DMSO=dimethyl sulfoxide)was synthesized by a simple method,and its crystal structure was characterized.In a three-electrode system,Co-BD,as the electrode material for supercapacitors,achieved a specific capacitance of 830 F·g^(-1)at 1 A·g^(-1),equivalent to a specific capacity of 116.4 mAh·g^(-1),and exhibited high-rate capability,reaching 212 F·g^(-1)at 20 A·g^(-1).Impressively,Co-BD||rGO(reduced graphene oxide),representing an asymmetrical supercapacitor,owns a higher energy density of 14.2 Wh·kg^(-1)at 0.80 kW·kg^(-1),and an excellent cycle performance(After 4000 cycles at 1 A·g^(-1),the capacitance retention was up to 94%).CCDC:2418872.展开更多
In order to improve the electrochemical hydrogen storage performance of the Mg2Ni-type electrode alloys, Mg in the alloy was partially substituted by La, and the nanocrystalline and amorphous Mg2Ni-type Mg20-xLaxNi10 ...In order to improve the electrochemical hydrogen storage performance of the Mg2Ni-type electrode alloys, Mg in the alloy was partially substituted by La, and the nanocrystalline and amorphous Mg2Ni-type Mg20-xLaxNi10 （x-=0, 2） alloys were synthesized by melt-spinning technique. The microstructures of the as-spun alloys were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The electrochemical hydrogen storage properties of the experimental alloys were tested. The results show that no amorphous phase is detected in the as-spun Mg20Ni10 alloy, but the as-spun Mg18La2Ni10 alloy holds a major amorphous phase. As La content increases from 0 to 2, the maximum discharge capacity of the as-spun （20 m/s） alloys rises from 96.5 to 387.1 mA.h/g, and the capacity retaining rate （S20） at the 20th cycle grows from 31.3% to 71.7%. Melt-spinning engenders an impactful effect on the electrochemical hydrogen storage performances of the alloys. With the increase in the spinning rate from 0 to 30 m/s, the maximum discharge capacity increases from 30.3 to 135.5 mA.h/g for the Mg20Ni10 alloy, and from 197.2 to 406.5 mA-h/g for the Mg18La2Ni10 alloy. The capacity retaining rate （S20） of the Mg2oNi10 alloy at the 20th cycle slightly falls from 36.7% to 27.1%, but it markedly mounts up from 37.3% to 78.3% for the Mg18La2Ni10 alloy.展开更多
Reversible solid oxide cell(RSOC)is a new energy conversion device with significant applications,especially for power grid peaking shaving.However,the reversible conversion process of power generation/energy storage p...Reversible solid oxide cell(RSOC)is a new energy conversion device with significant applications,especially for power grid peaking shaving.However,the reversible conversion process of power generation/energy storage poses challenges for the performance and stability of air electrodes.In this work,a novel high-entropy perovskite oxide La_(0.2)Pr_(0.2)Gd_(0.2)Sm_(0.2)Sr_(0.2)Co_(0.8)Fe_(0.2)O_(3−δ)(HE-LSCF)is proposed and investigated as an air electrode in RSOC.The electrochemical behavior of HE-LSCF was studied as an air electrode in both fuel cell and electrolysis modes.The polarization impedance(Rp)of the HE-LSCF electrode is only 0.25Ω·cm^(2) at 800℃ in an air atmosphere.Notably,at an electrolytic voltage of 2 V and a temperature of 800℃,the current density reaches up to 1.68 A/cm^(2).The HE-LSCF air electrode exhibited excellent reversibility and stability,and its electrochemical performance remains stable after 100 h of reversible operation.With these advantages,HE-LSCF is shown to be an excellent air electrode for RSOC.展开更多
Smart batteries play a key role in upgrading energy storage systems.However,they require a well-balanced integration of material structure,functional properties,and electrochemical performance,and their development is...Smart batteries play a key role in upgrading energy storage systems.However,they require a well-balanced integration of material structure,functional properties,and electrochemical performance,and their development is limited by conventional material systems in terms of energy density,response time,and functional integration.Carbon materials have emerged as a key solution for overcoming these problems due to their structural adjustability and multifunctional compatibility.Strategies for improving their electrochemical performance by changing the pore structure and interlayer spacing,as well as chemical functionalization,and composite design are analyzed,and their impact on improving the specific capacity and cycling stability of batteries is demonstrated.The unique advantages of carbon materials in realizing smart functions such as power supply,real-time monitoring and energy management in smart batteries are also discussed.Based on current progress in related fields,the prospects for the use of carbon materials in smart batteries are evaluated.展开更多
Hexagonal porous Nb2O5 was synthesized for the first time via a facile solid-state reaction.The structure and electrochemical properties have been optimized through tuning heating temperature.X-ray diffraction results...Hexagonal porous Nb2O5 was synthesized for the first time via a facile solid-state reaction.The structure and electrochemical properties have been optimized through tuning heating temperature.X-ray diffraction results indicate that pseudo hexagonal Nb2O5(TT-Nb2O5)and orthorhombic Nb2O5 have been synthesized at different temperatures.Hexagonal sheet and porous structure of Nb2O5 were characterized by scanning electron microscopy and N2-adsorption-desorption isotherms.The as-prepared TT-Nb2O5(heated at 600℃)shows the best performance with a remarkable charge capacity of 178 mA∙h/g at 0.2C,which is higher than that of T-Nb2O5.Even at 20℃,TT-Nb2O5 offers unprecedented rate capability up to 86 mA∙h/g.The high rate capacity is due to pseudocapacitive Li+intercalation mechanism of TT-Nb2O5.The reported results demonstrate that Nb2O5 with good crystal structure and high specific surface area is a powerful composite design for high-rate and safe anode materials.展开更多
Sb-based materials have been considered one of the most promising anode electrode materials for lithium-ion batteries,whereas they were commonly synthesized through time-consuming and costly processes.Here,Sb@Sb2O3/re...Sb-based materials have been considered one of the most promising anode electrode materials for lithium-ion batteries,whereas they were commonly synthesized through time-consuming and costly processes.Here,Sb@Sb2O3/reduced graphene oxide(Sb@Sb2O3/rGO)composite was successfully synthesized by a facile one-pot chemical method at ambient temperature.Based on the XRD and TGA analysis,the mass fractions of Sb and Sb2O3 in the Sb@Sb2O3/rGO composite are ca.34.05%and 26.6%,respectively.When used as an alternative electrode for lithium ion batteries,a high reversible capacity of 790.9 mA·h/g could be delivered after 200 cycles with the capacity retention of 93.8%at a current density of 200 mA/g.And a capacity of 260 mA·h/g could be maintained even at 2000 mA/g.These excellent electrochemical properties can be attributed to its well-constructed nanostructure.The Sb and Sb2O3 particles with size of 10 nm were tightly anchored on rGO sheets through electronic coupling,which could not only alleviate the stress induced by the volume expansion,suppress the aggregation of Sb and Sb2O3 particles,but also improve the electron transfer ability during cycling.展开更多
A reduced graphene oxide/Ni(OH)2 composite with excellent supercapacitive performance was synthesized by a facile hydrothermal route without organic solvents or templates used.XRD and SEM results reveal that the nicke...A reduced graphene oxide/Ni(OH)2 composite with excellent supercapacitive performance was synthesized by a facile hydrothermal route without organic solvents or templates used.XRD and SEM results reveal that the nickel hydroxide,which crystallizes into hexagonal β-Ni(OH)2 nanoflakes with a diameter less than 200 nm and a thickness of about 10 nm,is well combined with the reduced graphene oxide sheets.Electrochemical performance of the synthesized composite as an electrode material was investigated by cyclic voltammetry,electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements.Its specific capacitance is determined to be 1672 F/g at a scan rate of 2 mV/s,and 696 F/g at a high scan rate of 50 mV/s.After 2000 cycles at a current density of 10 A/g,the composite exhibits a specific capacitance of 969 F/g,retaining about 86% of its initial capacitance.The composite delivers a high energy density of 83.6 W·h/kg at a power density of 1.0 kW/kg.The excellent supercapacitive performance along with the easy synthesis method allows the synthesized composite to be promising for supercapacitor applications.展开更多
For the purpose of improving the electrochemical cycle stability of the La-Mg-Ni based A2BT-type electrode alloys, both reducing Mg content and substituting La with Pr were adopted. The Lao.8-xPrxMg0.2Ni3.15Co0.2A10.1...For the purpose of improving the electrochemical cycle stability of the La-Mg-Ni based A2BT-type electrode alloys, both reducing Mg content and substituting La with Pr were adopted. The Lao.8-xPrxMg0.2Ni3.15Co0.2A10.1Si0.05 （x=0, 0.1, 0.2, 0.3, 0.4） electrode alloys were fabricated by casting and annealing. The investigation on the structures and electrochemical performances of the alloys was performed. The obtained results reveal that the as-cast and annealed alloys comprise two major phases, （La, Mg）2Ni7 phase with the hexagonal Ce2NiT-type structure and LaNi5 phase with the hexagonal CaCus-type structure, as well as a little residual LaNi3 phase. It is also found that the addition of Pr element observably affects the electrochemical hydrogen storage characteristics of the alloys, just as the discharge capacity and high rate discharge ability （HRD） first rise then fall with the growing of Pr content, and among all the alloys, the as-cast and annealed （x=0.3） alloys generate the largest discharge capacities of 360.8 and 386.5 mA.h/g, respectively. Additionally, the electrochemical cycle stability of all the alloys markedly grows with the increase of Pr content. The capacity retaining rate （S100） at the 100th charging and discharging cycle is enhanced from 64.98% to 77.55% for the as-cast alloy, and from 76.60% to 95.72% for the as-annealed alloy by rising Pr content from 0 to 0.4. Furthermore, the substitution of Pr for La results in first increase and then decrease in the hydrogen diffusion coefficient （D）, the limiting current density （IL） as well as the electrochemical impedance.展开更多
Porous platinum electrodes were prepared by adding YSZ,as an active material,in platinum paste.Relationship between microstructure and electrochemical performance of O 2(g),Pt/YSZ electrode have been characterized by ...Porous platinum electrodes were prepared by adding YSZ,as an active material,in platinum paste.Relationship between microstructure and electrochemical performance of O 2(g),Pt/YSZ electrode have been characterized by SEM and cyclic voltammetry.Results showed that the microstructure of platinum electrode is a significant impact on the cyclic voltammetry.With the increase of platinum electrode's porosity,the area of three-phase boundary of O 2(g) /Pt/YSZ was increased.The electrochemical reactivity was also enhanced.These were presented as the increase of current density and cathode voltage in cyclic voltammetry.展开更多
Zinc-ion capacitors(ZICs),which consist of a capacitor-type electrode and a battery-type electrode,not only possess the high power density of supercapacitors and the high energy density of batteries,but also have othe...Zinc-ion capacitors(ZICs),which consist of a capacitor-type electrode and a battery-type electrode,not only possess the high power density of supercapacitors and the high energy density of batteries,but also have other advantages such as abundant resources,high safety and environmental friendliness.However,they still face problems such as insufficient specific capacitance,a short cycling life,and narrow operating voltage and temperature ranges,which are hindering their practical use.We provide a comprehensive overview of the fundamental theory of carbon-based ZICs and summarize recent research progress from three perspectives:the carbon cathode,electrolyte and zinc anode.The influence of the structure and surface chemical properties of the carbon materials on the capacitive performance of ZICs is considered together with theoretical guidance for advancing their development and practical use.展开更多
Sodium-sulfur(Na-S)and potassium-sulfur(K-S)batteries for use at room temperature have received widespread attention because of the abundance and low cost of their raw materials and their high energy density.However,t...Sodium-sulfur(Na-S)and potassium-sulfur(K-S)batteries for use at room temperature have received widespread attention because of the abundance and low cost of their raw materials and their high energy density.However,their development is restricted by the shuttling of polysulfides,large volume expansion and poor conductivity.To overcome these obstacles,an effective approach is to use carbon-based materials with abundant space for the sulfur that has sulfiphilic sites to immobilize it,and a high electrical conductivity.Hollow carbon spheres(HCSs)with a controllable structure and composition are promising for this purpose.We consider recent progress in optimizing the electrochemical performance of Na-/K-S batteries by using these materials.First,the advantages of HCSs,their synthesis methods,and strategies for preparing HCSs/sulfur composite materials are reviewed.Second,the use of HCSs in Na-/K-S batteries,along with mechanisms underlying the resulting performance improvement,are discussed.Finally,prospects for the further development of HCSs for metal−S batteries are presented.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
With increasing demand on energy density of lithium-ion battery,wide electrochemical window and safety performance are the crucial request for next generation electrolyte.Gel-electrolyte as a pioneer for electrolyte s...With increasing demand on energy density of lithium-ion battery,wide electrochemical window and safety performance are the crucial request for next generation electrolyte.Gel-electrolyte as a pioneer for electrolyte solidization development aims to solve the safety and electrochemical window problems.However,low ionic conductivity and poor physical performance prohibit its further application.Herein,a fast-ionic conductor(Li_(2.64)(Sc_(0.9)Ti_(0.1))_(2)(PO_(4))_(3))(LSTP)was added into poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)base gel-electrolyte to enhance mechanical properties and ionic conductivity.Evidences reveal that LSTP was able to weaken interforce between polymer chains,which increased the ionic conductibility and decreased interface resistance during the cycling significantly.The obtained LiFePO_(4)/hybrid gel-electrolyte/Li-metal coin cell exhibited excellent rate capacity(145 mA·h/g at 1C,95 mA·h/g at 3C,28℃)which presented a potential that can be comparable with commercialized liquid electrolyte system.展开更多
Alloy anodes were studied for pursuing Sn-based microcomposite synthesis, assembly and performance for lithium ion batteries. The self-assembled Sn-Co-C composites with nano-scaled microstructures were prepared via so...Alloy anodes were studied for pursuing Sn-based microcomposite synthesis, assembly and performance for lithium ion batteries. The self-assembled Sn-Co-C composites with nano-scaled microstructures were prepared via solution method and carbothermal technology. The morphology and physical structure were investigated with scanning electron microscope (SEM) and X-ray diffraction (XRD). The as-prepared materials were assembled to half cell coin for the purpose of discussing the galvanostatic cycling, cyclic voltammetry and rate-capability performance. Results reveal that nanoscaled CoSn 2 alloys covered with Sn and C layer by layer are wrapped by cross-linked porous carbon network to form spherical microstructure. This distinguishing feature of Sn-Co-C composites provides a possible solution to the problems of Sn particle aggregation and poor electron transport, and has strong effect on improving electrochemical performance.展开更多
The conversion reaction-based anode materials of sodium ion batteries have relatively high capacity;however,the application of these materials is limited by their structural collapse due to the poor structure stabilit...The conversion reaction-based anode materials of sodium ion batteries have relatively high capacity;however,the application of these materials is limited by their structural collapse due to the poor structure stability.In this work,MoSe_(2) nanosheets were synthesized by a solvothermal method.An organic solvent was intercalated into the MoSe_(2) materials to enlarge the interlayer spacing and improve the conductivity of the material.The MoSe_(2) material was coated with an organic pyrolysis carbon and then a uniform carbon layer was formed.The surface carbon hybridization of the nanosheet materials was realized by the introduction of heteroatoms during the sintering process.The as-prepared MoSe_(2)@N,P-C composites showed a superior rate performance as it could maintain the integrity of the morphology and structure under a high current density.The composites had a discharge specific capacity of 302.4 mA·h/g after 100 cycles at 0.5 A/g,and the capacity retention rate was 84.96%.展开更多
基金Projects(51371094,51161015)supported by the National Natural Science Foundations of ChinaProject(2011ZD10)supported by Natural Science Foundation of Inner Mongolia,China
文摘The La-Mg-Ni-based A2B7-type La0.5Mg0.2Ni3.3Co0.2Six （x=0-0.2） electrode alloys were prepared by casting and annealing. The influences of the additional silicon and the annealing treatment on the structure and electrochemical performances of the alloys were investigated systemically. Both of the analyses of XRD and SEM reveal that the as-cast and annealed alloys are of a multiphase structure, involving two main phases （La, Mg）2Ni7 and LaNi5 as well as one minor phase LaNi3. The addition of Si and annealing treatment bring on an evident change in the phase abundances and cell parameters of （La, Mg）2Ni7 and LaNi5 phase for the alloy without altering its phase structure. The phase abundances decrease from 74.3% （x=0） to 57.8% （x=0.2） for the （La, Mg）2Ni7 phase, and those of LaNi5 phase increase from 20.2% （x^0） to 37.3% （x=0.2）. As for the electrochemical measurements, adding Si and performing annealing treatment have engendered obvious impacts. The cycle stability of the alloys is improved dramatically, being enhanced from 80.3% to 93.7% for the as-annealed （950 ℃） alloys with Si content increasing from 0 to 0.2. However, the discharge capacity is reduced by adding Si, from 399.4 to 345.3 mA.h/g as the Si content increases from 0 to 0.2. Furthermore, such addition makes the electrochemical kinetic properties of the alloy electrodes first increase and then decrease. Also, it is found that the overall electrochemical properties of the alloys first augment and then fall with the annealing temperature rising.
基金Project(50571091) supported by the National Natural Science Foundation of ChinaProject(09C947) supported by the Scientific Research Fund of Hunan Provincial Education Department,China
文摘A LiFePO4/（C＋Fe2P） composite cathode material was prepared by a sol-gel method using Fe（NO3）3.9H20, LiAc·H2O）, NHaH2PO4 and citric acid as raw materials, and the physical properties and electrochemical performance of the composite cathode material were investigated by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and electrochemical tests. The Fe2P content, morphology and electrochemical performance of LiFePOa/（C＋Fe2P） composite depend on the calcination temperature. The optimized LiFePO4/（C＋FeeP） composite is prepared at 650 ~C and the optimized composite exhibits sphere-like morphology with porous structure and Fe2P content of about 3.2% （mass fraction）. The discharge capacity of the optimized LiFePO4/（C＋FeRP） at 0.1C is 156 and 161 mA.h/g at 25 and 55 ℃, respectively, and the corresponding capacity retentions are 96% after 30 cycles; while the capacity at 1C is 142 and 149 mA.h/g at 25 and 55 ℃, respectively, and the capacity still remains 135 and 142 mA-h/g after 30 cycles at 25 and 55℃, respectively.
基金Project(51772333) supported by the National Natural Science Foundation of China。
文摘Lithium(Li)-rich manganese(Mn)-based cathode Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2)(LRNCM)has attracted considerable attention owing to its high specific discharge capacity and low cost.However,unsatisfactory cycle performance and poor rate property hinder its large-scale application.The fast ionic conductor has been widely used as the cathode coating material because of its superior stability and excellent lithium-ion conductivity rate.In this study,Li_(1.2)Ni_(0.13)Co_(0.13)Mn_(0.54)O_(2) is modified by using Li_(1.4)Al_(0.4)Ti_(1.6)(PO_(4))_(3)(LATP)ionic conductor.The electrochemical test results show that the discharge capacity of the resulting LRNCM@LATP1 sample is 198 mA·h/g after 100 cycles at 0.2C,with a capacity retention of 81%.Compared with the uncoated pristine LRNCM(188.4 m A·h/g and 76%),LRNCM after the LATP modification shows superior cycle performance.Moreover,the lithium-ion diffusion coefficient D_(Li+)is a crucial factor affecting the rate performance,and the D_(Li+)of the LRNCM material is improved from 4.94×10^(-13) to 5.68×10^(-12)cm^(2)/s after modification.The specific capacity of LRNCM@LATP1 reaches 102.5 mA·h/g at 5C,with an improved rate performance.Thus,the modification layer can considerably enhance the electrochemical performance of LRNCM.
基金Project(2007BAE12B01) supported by the National Key Technology Research and Development Program of China
文摘Li4Ti5O12/C composite materials were synthesized by two-step solid state reaction method with glucose, sucrose, and starch as carbon sources, respectively. The effects of carbon sources on the structure, morphology, and electrochemical performance of Li4Ti5O12/C composite materials were investigated by SEM, XRD and electrochemical tests. The results indicate that carbon sources have almost no effect on the structure of Li4Ti5O12/C composite materials. The initial discharge capacities of the Li4Ti1O12/C composite materials are slightly lower than those of as-synthesized Li4Ti5O12. However, Li4Ti5O12/C composite materials show better electrochemical rate performance than the as-synthesized Li4Ti5O12. The capacity retention （79%） of the Li4Ti5O12/C composite materials with starch as carbon source, is higher than that of Li4Ti5O12/C composite materials with glucose and sucrose as carbon source at current rate of 2.0C.
基金Project(50604018) supported by the National Natural Science Foundation of China
文摘LiFePO4 was prepared by heating the pre-decomposed precursor mixtures sealed in vacuum quartz-tube. Three kinds of cooling modes including nature cooling, air quenching, and water quenching were applied to comparing the effects of cooling modes on the microstructure and electrochemical characteristics of the material. The results indicate that the water quenching mode can control overgrowth of the grain size of final product and improve its electrochemical performance compared with nature cooling mode and air quenching mode. The sample synthesized by using water quenching mode is of the highest reversible discharge specific capacity and the best cyclic electrochemical performance, demonstrating the first discharge capacity of 138.1 mA·h/g at 0.1C rate and the total loss of capacity of 3.11% after 20 cycles.
文摘A low-cost 1D cobalt-based coordination polymer(CP)[Co(BGPD)(DMSO)_(2)(H_(2)O)_(2)](Co-BD;H2BGPD=N,N'-bis(glycinyl)pyromellitic diimide;DMSO=dimethyl sulfoxide)was synthesized by a simple method,and its crystal structure was characterized.In a three-electrode system,Co-BD,as the electrode material for supercapacitors,achieved a specific capacitance of 830 F·g^(-1)at 1 A·g^(-1),equivalent to a specific capacity of 116.4 mAh·g^(-1),and exhibited high-rate capability,reaching 212 F·g^(-1)at 20 A·g^(-1).Impressively,Co-BD||rGO(reduced graphene oxide),representing an asymmetrical supercapacitor,owns a higher energy density of 14.2 Wh·kg^(-1)at 0.80 kW·kg^(-1),and an excellent cycle performance(After 4000 cycles at 1 A·g^(-1),the capacitance retention was up to 94%).CCDC:2418872.
基金Projects(50871050, 50961009) supported by the National Natural Science Foundation of ChinaProject(2010ZD05) supported by the Natural Science Foundation of Inner Mongolia, ChinaProject(NJzy08071) supported by the Higher Education Science Research Project of Inner Mongolia, China
文摘In order to improve the electrochemical hydrogen storage performance of the Mg2Ni-type electrode alloys, Mg in the alloy was partially substituted by La, and the nanocrystalline and amorphous Mg2Ni-type Mg20-xLaxNi10 （x-=0, 2） alloys were synthesized by melt-spinning technique. The microstructures of the as-spun alloys were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The electrochemical hydrogen storage properties of the experimental alloys were tested. The results show that no amorphous phase is detected in the as-spun Mg20Ni10 alloy, but the as-spun Mg18La2Ni10 alloy holds a major amorphous phase. As La content increases from 0 to 2, the maximum discharge capacity of the as-spun （20 m/s） alloys rises from 96.5 to 387.1 mA.h/g, and the capacity retaining rate （S20） at the 20th cycle grows from 31.3% to 71.7%. Melt-spinning engenders an impactful effect on the electrochemical hydrogen storage performances of the alloys. With the increase in the spinning rate from 0 to 30 m/s, the maximum discharge capacity increases from 30.3 to 135.5 mA.h/g for the Mg20Ni10 alloy, and from 197.2 to 406.5 mA-h/g for the Mg18La2Ni10 alloy. The capacity retaining rate （S20） of the Mg2oNi10 alloy at the 20th cycle slightly falls from 36.7% to 27.1%, but it markedly mounts up from 37.3% to 78.3% for the Mg18La2Ni10 alloy.
基金supported by Fundamental Research Funds for the Central Universities(2023KYJD1008)the Science Research Projects of the Anhui Higher Education Institutions of China(2022AH051582).
文摘Reversible solid oxide cell(RSOC)is a new energy conversion device with significant applications,especially for power grid peaking shaving.However,the reversible conversion process of power generation/energy storage poses challenges for the performance and stability of air electrodes.In this work,a novel high-entropy perovskite oxide La_(0.2)Pr_(0.2)Gd_(0.2)Sm_(0.2)Sr_(0.2)Co_(0.8)Fe_(0.2)O_(3−δ)(HE-LSCF)is proposed and investigated as an air electrode in RSOC.The electrochemical behavior of HE-LSCF was studied as an air electrode in both fuel cell and electrolysis modes.The polarization impedance(Rp)of the HE-LSCF electrode is only 0.25Ω·cm^(2) at 800℃ in an air atmosphere.Notably,at an electrolytic voltage of 2 V and a temperature of 800℃,the current density reaches up to 1.68 A/cm^(2).The HE-LSCF air electrode exhibited excellent reversibility and stability,and its electrochemical performance remains stable after 100 h of reversible operation.With these advantages,HE-LSCF is shown to be an excellent air electrode for RSOC.
文摘Smart batteries play a key role in upgrading energy storage systems.However,they require a well-balanced integration of material structure,functional properties,and electrochemical performance,and their development is limited by conventional material systems in terms of energy density,response time,and functional integration.Carbon materials have emerged as a key solution for overcoming these problems due to their structural adjustability and multifunctional compatibility.Strategies for improving their electrochemical performance by changing the pore structure and interlayer spacing,as well as chemical functionalization,and composite design are analyzed,and their impact on improving the specific capacity and cycling stability of batteries is demonstrated.The unique advantages of carbon materials in realizing smart functions such as power supply,real-time monitoring and energy management in smart batteries are also discussed.Based on current progress in related fields,the prospects for the use of carbon materials in smart batteries are evaluated.
基金Projects(51974137,51774150)supported by the National Natural Science Foundation of ChinaProject(2020M671361)supported by China Postdoctoral Science Foundation。
文摘Hexagonal porous Nb2O5 was synthesized for the first time via a facile solid-state reaction.The structure and electrochemical properties have been optimized through tuning heating temperature.X-ray diffraction results indicate that pseudo hexagonal Nb2O5(TT-Nb2O5)and orthorhombic Nb2O5 have been synthesized at different temperatures.Hexagonal sheet and porous structure of Nb2O5 were characterized by scanning electron microscopy and N2-adsorption-desorption isotherms.The as-prepared TT-Nb2O5(heated at 600℃)shows the best performance with a remarkable charge capacity of 178 mA∙h/g at 0.2C,which is higher than that of T-Nb2O5.Even at 20℃,TT-Nb2O5 offers unprecedented rate capability up to 86 mA∙h/g.The high rate capacity is due to pseudocapacitive Li+intercalation mechanism of TT-Nb2O5.The reported results demonstrate that Nb2O5 with good crystal structure and high specific surface area is a powerful composite design for high-rate and safe anode materials.
基金Project(51462032)supported by the National Natural Science Foundation of ChinaProject(17JR5RA066)supported by the Foundation for Distinguished Young Scholars of Gansu Province,China
文摘Sb-based materials have been considered one of the most promising anode electrode materials for lithium-ion batteries,whereas they were commonly synthesized through time-consuming and costly processes.Here,Sb@Sb2O3/reduced graphene oxide(Sb@Sb2O3/rGO)composite was successfully synthesized by a facile one-pot chemical method at ambient temperature.Based on the XRD and TGA analysis,the mass fractions of Sb and Sb2O3 in the Sb@Sb2O3/rGO composite are ca.34.05%and 26.6%,respectively.When used as an alternative electrode for lithium ion batteries,a high reversible capacity of 790.9 mA·h/g could be delivered after 200 cycles with the capacity retention of 93.8%at a current density of 200 mA/g.And a capacity of 260 mA·h/g could be maintained even at 2000 mA/g.These excellent electrochemical properties can be attributed to its well-constructed nanostructure.The Sb and Sb2O3 particles with size of 10 nm were tightly anchored on rGO sheets through electronic coupling,which could not only alleviate the stress induced by the volume expansion,suppress the aggregation of Sb and Sb2O3 particles,but also improve the electron transfer ability during cycling.
基金Project(KJ2012A045) supported by the Natural Science Foundation of Education Commission of Anhui Province,China
文摘A reduced graphene oxide/Ni(OH)2 composite with excellent supercapacitive performance was synthesized by a facile hydrothermal route without organic solvents or templates used.XRD and SEM results reveal that the nickel hydroxide,which crystallizes into hexagonal β-Ni(OH)2 nanoflakes with a diameter less than 200 nm and a thickness of about 10 nm,is well combined with the reduced graphene oxide sheets.Electrochemical performance of the synthesized composite as an electrode material was investigated by cyclic voltammetry,electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements.Its specific capacitance is determined to be 1672 F/g at a scan rate of 2 mV/s,and 696 F/g at a high scan rate of 50 mV/s.After 2000 cycles at a current density of 10 A/g,the composite exhibits a specific capacitance of 969 F/g,retaining about 86% of its initial capacitance.The composite delivers a high energy density of 83.6 W·h/kg at a power density of 1.0 kW/kg.The excellent supercapacitive performance along with the easy synthesis method allows the synthesized composite to be promising for supercapacitor applications.
基金Projects(51161015,50961009) supported by the National Natural Science Foundation of ChinaProject(2011AA03A408) supported by the National High Technology Research and Development Program of ChinaProjects(2011ZD10,2010ZD05) supported by the Natural Science Foundation of Inner Mongolia,China
文摘For the purpose of improving the electrochemical cycle stability of the La-Mg-Ni based A2BT-type electrode alloys, both reducing Mg content and substituting La with Pr were adopted. The Lao.8-xPrxMg0.2Ni3.15Co0.2A10.1Si0.05 （x=0, 0.1, 0.2, 0.3, 0.4） electrode alloys were fabricated by casting and annealing. The investigation on the structures and electrochemical performances of the alloys was performed. The obtained results reveal that the as-cast and annealed alloys comprise two major phases, （La, Mg）2Ni7 phase with the hexagonal Ce2NiT-type structure and LaNi5 phase with the hexagonal CaCus-type structure, as well as a little residual LaNi3 phase. It is also found that the addition of Pr element observably affects the electrochemical hydrogen storage characteristics of the alloys, just as the discharge capacity and high rate discharge ability （HRD） first rise then fall with the growing of Pr content, and among all the alloys, the as-cast and annealed （x=0.3） alloys generate the largest discharge capacities of 360.8 and 386.5 mA.h/g, respectively. Additionally, the electrochemical cycle stability of all the alloys markedly grows with the increase of Pr content. The capacity retaining rate （S100） at the 100th charging and discharging cycle is enhanced from 64.98% to 77.55% for the as-cast alloy, and from 76.60% to 95.72% for the as-annealed alloy by rising Pr content from 0 to 0.4. Furthermore, the substitution of Pr for La results in first increase and then decrease in the hydrogen diffusion coefficient （D）, the limiting current density （IL） as well as the electrochemical impedance.
文摘Porous platinum electrodes were prepared by adding YSZ,as an active material,in platinum paste.Relationship between microstructure and electrochemical performance of O 2(g),Pt/YSZ electrode have been characterized by SEM and cyclic voltammetry.Results showed that the microstructure of platinum electrode is a significant impact on the cyclic voltammetry.With the increase of platinum electrode's porosity,the area of three-phase boundary of O 2(g) /Pt/YSZ was increased.The electrochemical reactivity was also enhanced.These were presented as the increase of current density and cathode voltage in cyclic voltammetry.
文摘Zinc-ion capacitors(ZICs),which consist of a capacitor-type electrode and a battery-type electrode,not only possess the high power density of supercapacitors and the high energy density of batteries,but also have other advantages such as abundant resources,high safety and environmental friendliness.However,they still face problems such as insufficient specific capacitance,a short cycling life,and narrow operating voltage and temperature ranges,which are hindering their practical use.We provide a comprehensive overview of the fundamental theory of carbon-based ZICs and summarize recent research progress from three perspectives:the carbon cathode,electrolyte and zinc anode.The influence of the structure and surface chemical properties of the carbon materials on the capacitive performance of ZICs is considered together with theoretical guidance for advancing their development and practical use.
文摘Sodium-sulfur(Na-S)and potassium-sulfur(K-S)batteries for use at room temperature have received widespread attention because of the abundance and low cost of their raw materials and their high energy density.However,their development is restricted by the shuttling of polysulfides,large volume expansion and poor conductivity.To overcome these obstacles,an effective approach is to use carbon-based materials with abundant space for the sulfur that has sulfiphilic sites to immobilize it,and a high electrical conductivity.Hollow carbon spheres(HCSs)with a controllable structure and composition are promising for this purpose.We consider recent progress in optimizing the electrochemical performance of Na-/K-S batteries by using these materials.First,the advantages of HCSs,their synthesis methods,and strategies for preparing HCSs/sulfur composite materials are reviewed.Second,the use of HCSs in Na-/K-S batteries,along with mechanisms underlying the resulting performance improvement,are discussed.Finally,prospects for the further development of HCSs for metal−S batteries are presented.
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.
基金Projects(51974368,51774333) supported by the National Natural Science Foundation of ChinaProject(2020JJ2048) supported by the Hunan Provincial Natural Science Foundation of China。
文摘With increasing demand on energy density of lithium-ion battery,wide electrochemical window and safety performance are the crucial request for next generation electrolyte.Gel-electrolyte as a pioneer for electrolyte solidization development aims to solve the safety and electrochemical window problems.However,low ionic conductivity and poor physical performance prohibit its further application.Herein,a fast-ionic conductor(Li_(2.64)(Sc_(0.9)Ti_(0.1))_(2)(PO_(4))_(3))(LSTP)was added into poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)base gel-electrolyte to enhance mechanical properties and ionic conductivity.Evidences reveal that LSTP was able to weaken interforce between polymer chains,which increased the ionic conductibility and decreased interface resistance during the cycling significantly.The obtained LiFePO_(4)/hybrid gel-electrolyte/Li-metal coin cell exhibited excellent rate capacity(145 mA·h/g at 1C,95 mA·h/g at 3C,28℃)which presented a potential that can be comparable with commercialized liquid electrolyte system.
基金Projects(51074185, 51274240) supported by the National Natural Science Foundation of ChinaProject supported by the Fundamental Research Funds for the Central Universities
文摘Alloy anodes were studied for pursuing Sn-based microcomposite synthesis, assembly and performance for lithium ion batteries. The self-assembled Sn-Co-C composites with nano-scaled microstructures were prepared via solution method and carbothermal technology. The morphology and physical structure were investigated with scanning electron microscope (SEM) and X-ray diffraction (XRD). The as-prepared materials were assembled to half cell coin for the purpose of discussing the galvanostatic cycling, cyclic voltammetry and rate-capability performance. Results reveal that nanoscaled CoSn 2 alloys covered with Sn and C layer by layer are wrapped by cross-linked porous carbon network to form spherical microstructure. This distinguishing feature of Sn-Co-C composites provides a possible solution to the problems of Sn particle aggregation and poor electron transport, and has strong effect on improving electrochemical performance.
基金Project(51572300) supported by the National Natural Science Foundation of China。
文摘The conversion reaction-based anode materials of sodium ion batteries have relatively high capacity;however,the application of these materials is limited by their structural collapse due to the poor structure stability.In this work,MoSe_(2) nanosheets were synthesized by a solvothermal method.An organic solvent was intercalated into the MoSe_(2) materials to enlarge the interlayer spacing and improve the conductivity of the material.The MoSe_(2) material was coated with an organic pyrolysis carbon and then a uniform carbon layer was formed.The surface carbon hybridization of the nanosheet materials was realized by the introduction of heteroatoms during the sintering process.The as-prepared MoSe_(2)@N,P-C composites showed a superior rate performance as it could maintain the integrity of the morphology and structure under a high current density.The composites had a discharge specific capacity of 302.4 mA·h/g after 100 cycles at 0.5 A/g,and the capacity retention rate was 84.96%.
