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
A series of CexPr1-xO2-δ mixed oxides were synthesized by sol-gel met hod and characterized by Raman and XRD techniques. When x value was changed from 1.0 to 0.5, only a cubic phase CeO2 was observed. The samples wer...A series of CexPr1-xO2-δ mixed oxides were synthesized by sol-gel met hod and characterized by Raman and XRD techniques. When x value was changed from 1.0 to 0.5, only a cubic phase CeO2 was observed. The samples were very well cr ystallized on decreasing x from 0.50 to 0.99. For CexPr1-xO2-δ samples 465 cm-1 and 1 150 cm-1 Raman peaks are attributed to the Raman active F2g mode of CeO2. The broad peak at about 570 cm-1 in the region of 0.3 ≤ x ≤ 0.99 can be linke d to lattice defects resulting in oxygen vacancies. The new band at about 195 cm -1 may be attributed to the asymmetric vibration caused by the formation of oxyg en vacancies. Calcination temperatures had great effect on the peak intensity fo r CeO2 but less effect on Ce0.8Pr0.2O2-δ in Raman spectra. It might be due to t he transformation of the colors for the mixed oxides, the insertion of Pr atom i nto the ceria lattice could enhance the sintering resistance and thermal stabili ty of the mixed oxides.展开更多
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A series of CexPr1-xO2-δ mixed oxides were synthesized by sol-gel met hod and characterized by Raman and XRD techniques. When x value was changed from 1.0 to 0.5, only a cubic phase CeO2 was observed. The samples were very well cr ystallized on decreasing x from 0.50 to 0.99. For CexPr1-xO2-δ samples 465 cm-1 and 1 150 cm-1 Raman peaks are attributed to the Raman active F2g mode of CeO2. The broad peak at about 570 cm-1 in the region of 0.3 ≤ x ≤ 0.99 can be linke d to lattice defects resulting in oxygen vacancies. The new band at about 195 cm -1 may be attributed to the asymmetric vibration caused by the formation of oxyg en vacancies. Calcination temperatures had great effect on the peak intensity fo r CeO2 but less effect on Ce0.8Pr0.2O2-δ in Raman spectra. It might be due to t he transformation of the colors for the mixed oxides, the insertion of Pr atom i nto the ceria lattice could enhance the sintering resistance and thermal stabili ty of the mixed oxides.
