Al_(2)O_(3)/LiAlO_(2)协同提升LiNi_(0.92)Co_(0.04)Mn_(0.04)O_(2)正极材料循环稳定性的研究  

Study on improving the cycling stability of LiNi_(0.92)Co_(0.04)Mn_(0.04)O_(2) cathode material by synergistic Al_(2)O_(3)/LiAlO_(2)

作　　者：牛小伟 李妍泽[2] NIU Xiaowei;LI Yanze(Henan Intelligent Safety Engineering Research Center for Rail Transit,Zhengzhou 450018,China;Zhengzhou Railway Vocational Technical College,Zhengzhou 450052,China)

机构地区：[1]河南省轨道交通智能安全工程技术研究中心,郑州450018 [2]郑州铁路职业技术学院,郑州450052

出　　处：《有色金属科学与工程》2024年第2期228-236,共9页Nonferrous Metals Science and Engineering

基　　金：国家自然科学基金青年基金资助项目(62003313)。

摘　　要：锂离子电池(LIBs)是最普遍的储能设备之一,高镍LiNi_(0.92)Co_(0.04)Mn_(0.04)O_(2)正极因其放电比容量高而备受关注,然而,在长循环的过程中,由于正极表面的活性物质发生了化学和结构变化,LIBs的能量存储能力会随着循环的进行而减弱。理解和缓解这些退化机制是减少容量衰退的关键,从而提高锂离子电池的循环寿命。包覆是常见的改性手段,可改善高镍LiNi_(0.92)Co_(0.04)Mn_(0.04)O_(2)正极界面稳定性并降低表面降解的程度。但是,常规包覆方法形成的包覆层的厚度和均匀性难以调控,为了改进此问题,本研究建立了一种Al_(2)O_(3)/LiAlO_(2)薄膜,对LiNi_(0.92)Co_(0.04)Mn_(0.04)O_(2)具有协同改性效应,可形成厚度均匀的双包覆层,增强正极材料的循环性能和结构稳定性。研究结果表明,Al_(2)O_(3)/LiAlO_(2)双包覆层可以有效抑制不可逆相变,提高材料的结构稳定性。改性的材料展现出优异的循环稳定性,在2.75~4.40V电压范围内循环200圈,放电比容量为141.2 mAh/g,容量保持率高达76.1%。本研究为商业化正极材料界面的改性提供了新的思路。Lithium-ion batteries(LIBs)are one of the most common energy storage devices,and the high nickel LiNi_(0.92)Co_(0.04)Mn_(0.04)O_(2) positive electrode has attracted much attention due to its high specific discharge capacity.However,the energy storage capacity of LIBs will be weakened with the cycle due to the chemical and structural changes of active substances on the surface of the positive electrode during the long cycle.Understanding and mitigating these degradation mechanisms is key to reducing capacity degradation and improving the cycle life of lithium-ion batteries.Coating is a common modification method,which can improve the stability of high nickel LiNi_(0.92)Co_(0.04)Mn_(0.04)O_(2) positive electrode interface and reduce the surface degradation degree.However,the thickness and uniformity of the coating layer formed by conventional coating methods are difficult to regulate.In order to improve this problem,the co-modification effect of the Al_(2)O_(3)/LiAlO_(2) thin film on LiNi_(0.92)Co_(0.04)Mn_(0.04)O_(2) was reported in this paper.The formed double coating layer with uniform thickness enhanced the cycle performance and structural stability of the cathode material.The results showed that the Al_(2)O_(3)/LiAlO_(2) double coating layer could effectively inhibit the irreversible phase transformation and improve the structural stability of the material.The modified material exhibited excellent cyclic stability with a discharge specific capacity of 141.2 mAh/g and a capacity retention of 76.1%at a voltage range of 2.75 to 4.40 V for 200 cycles.This work provides a new way to the modification for the interface of commercial cathode materials.

关 键 词：锂离子电池 均匀性 Al_(2)O_(3)/LiAlO_(2)双包覆层 容量保持率 

分 类 号：TG132[一般工业技术—材料科学与工程] TM912[金属学及工艺—合金]