电化学（中英文）2025，Vol.31Issue(2)：17-27,11.DOI:10.61558/2993-074X.3515
铜取代型Li2Ni1-xCuxO2正极补锂剂提升石墨/磷酸铁锂电池循环寿命
Enhancing Cycle Life of Graphite‖LiFePO4 Batteries via Copper Substituted Li2Ni1-xCuxO2 Cathode Prelithiation Additive
摘要
Abstract
Lithium nickel oxide(Li2NiO2),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 Li2NiO2 suffers from inferior delithiation kinetics during the first cycle.Herein,we investigated the effects of the cost-effective copper substituted Li2Ni1-xCuxO2(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‖LiFePO4 battery.The X-ray diffraction(XRD)refinement result demonstrated that Cu substitution strategy could be favorable for eliminating the NiOx 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 Li2Ni0.7Cu0.3O2 delivered a high delithiation capacity of 437 mAh·g-1,around 8%above that of the pristine Li2NiO2.Furthermore,a graphite‖LiFePO4 pouch cell with a nominal capacity of 3000 mAh demonstrated a notably improved reversible capacity,energy density and cycle life through introducing 2 wt%Li2Ni0.7Cu0.3O2 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 Li2Ni0.7Cu0.3O2 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 Li2Ni0.7Cu0.3O2 additive may offer advantages such as lower cost,lower delithiation voltage and higher prelithiation capacity compared with Li2NiO2,making it a promising candidate of cathode prelithiation additive for next-generation LIBs.关键词
Li2Ni1-xCuxO2/正极补锂剂/磷酸铁锂电池/循环寿命/电网储能Key words
Li2Ni1-xCuxO2/Cathode prelithiation additive/LiFePO4 battery/Cycle life/Grid energy storage引用本文复制引用
郑建明,张静文,焦天鹏..铜取代型Li2Ni1-xCuxO2正极补锂剂提升石墨/磷酸铁锂电池循环寿命[J].电化学（中英文）,2025,31(2):17-27,11.基金项目
This work is supported by the Significant Science and Technology Project in Xiamen(Future Industry Field)(Grant No.3502Z20231057). （Future Industry Field）
