深冷处理对锂离子电池正极尖晶石锰酸锂结构及性能的影响  

Effects of cryogenic treatment on the structure and performance of spinel lithium manganese cathode for lithium-ion battery

作　　者：刘超帅 李振京 范广新[1] 孟德轩 蔡海洋 Liu Chaoshuai;Li Zhenjing;Fan Guangxin;Meng Dexuan;Cai Haiyang(School of Materials Science and Engineering,Henan Polytechnic University,Jiaozuo 454000;LongBai Group Co.,Ltd.,Jiaozuo 454000)

机构地区：[1]河南理工大学材料科学与工程学院,焦作454000 [2]龙佰集团股份有限公司,焦作454000

出　　处：《化工新型材料》2025年第2期170-174,共5页New Chemical Materials

基　　金：国家自然科学基金(U1804135和51671080);河南省创新人才计划项目(194200510019)。

摘　　要：用液氮在-150℃下对锂离子电池正极材料LiMn_(2)O_(4)进行深冷处理,通过X射线衍射仪(XRD)、扫描电镜(SEM)和电化学性能等表征手段对材料的结构、形貌及电化学性能进行了测试。结果表明:深冷处理不改变LiMn_(2)O_(4)的立方尖晶石结构,但对电化学性能影响显著。当处理时长为30min时,效果最佳,材料的大倍率放电能力及循环性能提升明显,10C条件下放电比容量由原始的45.2mAh/g提高到65.6mAh/g,200周循环容量保持率(1C)高达97.9%。究其原因:深冷处理使电极颗粒产生微裂纹,电解液透过微裂纹渗入到颗粒的内部,增加了正极与电解液之间的有效接触面积,缩短了锂离子的输运路径,降低了电极极化和电荷转移阻抗,从而提升了材料的大倍率性能;同时,裂纹的存在缓解了锂离子在反复脱嵌过程中引起的电极体积变化,释放了晶格畸变而产生的应力,使材料结构的稳定性增加,循环性能提升。LiMn_(2)O_(4)cathode material for Li-ion battery was subjected to cryogenic treatment with liquid nitrogen at-150℃.The structure,morphology and electrochemical properties of the material were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and electrochemical test methods.The results showed that cryogenic treatment could influence the electrochemical performance of the cathode significantly without changing the crystal structure of LiMn_(2)O_(4).The optimum high-rate discharge capability and cycle performance of the material were achieved during 30 minutes cryogenic treatment.The discharge specific capacity at 10C increased from the original 45.2mAh/g to 65.6mAh/g,and the capacity retention at 1C after 200 cycles was as high as 97.9%.The reasons for the improvement of high-rate capability and cycle performance were that cryogenic treatment caused micro-cracks in the electrode particles,and liquid electrolyte infiltrated into the interior of the particle through the micro-cracks,which increased the effective contact area between cathode and electrolyte,shorten lithium diffusion pathways,and lower electrode polarization and charge transfer resistance,thereby improving the high-rate performance of the cathode.In addition,the cracks provided room to buffer the volume changes during charge-discharge and released the stress caused by lattice distortion,which improved the structural stability and cycle performance of the material.

关 键 词：深冷处理 锂离子电池 正极材料 锰酸锂 电化学性能 

分 类 号：TQ152[化学工程—电化学工业]