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高性能磷酸铁锂电池补锂技术及机制OA北大核心CSTPCD

Study on technology and mechanism of prelithiation for high-performance lithium iron phosphate battery

中文摘要英文摘要

本工作采用正极磷酸铁锂(LiFePO4,LFP)搭配高容量石墨掺硅负极体系,以商业化富锂镍酸锂(Li2NiO2,LNO)作为正极补锂添加剂,探究补锂技术对磷酸铁锂电池性能的影响及作用机制.通过对LNO的电化学性能、脱锂前后的结构组成与微观形貌变化进行测试与分析,发现LNO的不可逆容量可达212.1 mAh/g,而且脱锂后的LNO主要以仍具活性的Li0.63Ni1.02O2形式存在.然后,将一定量的LNO添加至LFP正极浆料中制作成32 Ah软包电池,并进行容量、倍率、电化学阻抗和循环寿命等性能的测试与研究.结果表明:与基准组相比,添加质量分数3%的LNO补锂剂可以显著提升磷酸铁锂电池的性能,补锂组的能量密度和循环寿命分别提高4.9%和50%.此外,结合三电极测试方法,阐明了补锂技术对循环性能提升的作用机制.添加过量的正极补锂剂可促使部分活性锂预存于负极侧,在循环过程中进行缓慢释放,确保长期稳定的锂损失补偿,从而改善锂离子电池的循环寿命.该研究有助于推动正极补锂技术在储能电池中的应用,不仅为高性能磷酸铁锂电池的设计与开发提供理论和实验依据,也为硅基负极材料的商业化应用奠定基础.

In this work,Li2NiO2(LNO)is employed as a cathode prelithiation additive for lithium iron phosphate(LFP)cathodes,paired with a high-capacity graphite-doped silicon oxide anode,to investigate the effects and mechanisms of prelithiation technology on LFP batteries.The electrochemical performance,structural composition,and surface morphology of LNO were meticulously evaluated,revealing that LNO possesses an irreversible capacity of 212.1 mAh/g,primarily comprising active Li0.63Ni1.02O2 postdelithiation.Subsequently,a 32 Ah pouch cell was fabricated by integrating 3%LNO into the cathode slurry,leading to a notable enhancement in the performance of the LFP batteries.Compared to the control group,the energy density and cycle life of the LFP batteries with LNO were increased by 4.9%and 50%,respectively.Moreover,the contribution of prelithiation technology to cycle stability was elucidated using a three-electrode method,revealing that an excessive quantity of cathode prelithiation additive could lead to the retention of active lithium ions on the anode.These ions are gradually released during cycling,ensuring a sustained replenishment of active lithium ions,thereby augmenting the cycle life of lithium-ion batteries.This study advances the application of cathode prelithiation technology in energy storage systems,providing both theoretical and experimental insights for the design and development of high-performance LFP batteries and facilitating the large-scale adoption of silicon-based anode materials.

姜媛媛;傅继澎;屠芳芳;张芳平;王盈来;蔡佳文;杨东辉;李艳红;相佳媛;夏新辉

浙江南都电源动力股份有限公司,浙江 杭州 311300||浙江工业大学材料科学与工程学院,浙江 杭州 310014浙江南都电源动力股份有限公司,浙江 杭州 311300||中国计量大学光学与电子科技学院,浙江 杭州 310018浙江南都电源动力股份有限公司,浙江 杭州 311300浙江工业大学材料科学与工程学院,浙江 杭州 310014

化学

磷酸铁锂电池;正极补锂添加剂;硅基负极;能量密度;循环寿命

lithium iron phosphate battery;cathode prelithiation additive;silicon-based anode;energy density;cycle life

《储能科学与技术》 2024 (005)

1435-1442 / 8

浙江省科技计划项目(2022C01160).

10.19799/j.cnki.2095-4239.2023.0924

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