富锂锰基正极材料的硫掺杂协同Cu_(9)S_(5)包覆改性  

Modified Lithium-Rich Manganese-Based Cathode Material by the Synergistic Effect of Sulfur Doping and Cu_(9)S_(5) Coating

作　　者：聂祥坤 乔营 孙威[1] 田雪文 孙红梅[1] 慈立杰 NIE Xiangkun;QIAO Ying;SUN Wei;TIAN Xuewen;SUN Hongmei;CI Lijie(Sports Science Research Institute,Shandong Sport University,Jinan 250102,Shandong,China;School of Materials Science&Engineering,Shandong University,Jinan 250061,Shandong,China)

机构地区：[1]山东体育学院体育科学研究院,山东济南250102 [2]山东大学材料科学与工程学院,山东济南250061

出　　处：《武汉大学学报（理学版）》2024年第5期587-594,共8页Journal of Wuhan University:Natural Science Edition

基　　金：山东省自然科学基金青年项目(ZR2022QE179)。

摘　　要：采用溶胶凝胶法制备富锂锰基正极材料Li_(1.2)Mn_(0.54)Co_(0.13)Ni_(0.13)O_(2)(LMO),并以硫代乙酰胺和硝酸铜作为硫源和铜源,通过溶剂热法结合高温煅烧工艺对LMO进行S^(2-)掺杂和Cu_(9)S_(5)包覆,实现了LMO的表面改性。结果表明,用电负性较弱和离子半径较大的S^(2-)代替O^(2-),能够诱导LMO结构产生氧空穴,并调节结构中过渡金属元素的电子云排布;用电子电导率较高的Cu_(9)S_(5)包覆,能够有效缓解S^(2-)掺杂的问题,并抑制界面副反应。改性后,质量分数1%Cu_(9)S_(5)包覆协同S^(2-)掺杂的富锂锰基正极材料(1%CS@LMOS)具有最高的首圈放电比容量(290.6 mAh/g)和首圈库仑效率(84.07%)、优异的倍率性能(5 C,151 mAh/g)和循环稳定性(1 C,100圈,容量保持率92.76%)。此外,在充放电过程中,1%CS@LMOS材料的锂离子表观扩散速率均显著高于未改性材料。此改性方法有效提升了富锂锰基正极材料的电化学性能。A lithium-rich manganese-based cathode material of Li_(1.2)Mn_(0.54)Co_(0.13)Ni_(0.13)O_(2)(LMO)was prepared by using sol-gel method.Subsequently,surface modification of LMO is achieved through S^(2-)doping and Cu_(9)S_(5) coating using thioacetamide and copper nitrate as raw materials,via a solvothermal process combined with high-temperature calcination.The results indicate that substituting O^(2-)with S^(2-),which has a weaker electronegativity and larger ionic radius,can induce oxygen vacancies in the LMO structure and adjust the electronic cloud distribution of transition metal elements within the structure.The high electronic conductivity of the Cu_(9)S_(5) coating layer effectively alleviates the issues caused by S^(2-)doping and suppresses interfacial side reactions.After modification,the lithium-rich manganese-based cathode material with 1%Cu_(9)S_(5) coating and S^(2-)doping(1%CS@LMOS)exhibits the highest initial discharge specific capacity(290.6 mAh/g)and initial Coulombic efficiency(84.07%),excellent rate performance(151 mAh/g at 5 C)and cycling stability(92.76%,capacity retention after 100 cycles at 1 C).In addition,the apparent lithium ion diffusion rate of 1%CS@LMOS during charge and discharge processes is significantly higher than that of the unmodified material.This modification method effectively improves the electrochemical performance of lithium-rich manganese-based cathode materials.

关 键 词：锂离子电池 锰基正极材料 电化学性能 包覆 掺杂 改性 

分 类 号：O614[理学—无机化学]