Effect of overcharge on Li(Ni0.5Mn0.3Co0.2)O2/graphite lithium ion cells with poly(vinylidene fluoride) binder. III — Chemical changes in the cathode

Overcharge Cycling Effect on the Surface Layers and Crystalline Structure of LiFePO4 Cathodes of Li-Ion Batteries

“…Another cathode material, nickel rich-layered oxide LiNi 1−x−y Co x Mn y O 2 has a high specific capacity, but due to the high discharge voltage, its stability and safety still require substantial improvement [10,[18][19][20][21]. The structural changes were detected in the anode and the cathode of the overcharged cells, indicating migration of the transition metals to the anode, loss of electrodes integrity, and irreversible Li loss from the cathode [22][23][24][25]. As a result, the market share of the low-voltage cathode material LiFePO 4 (LFP) is currently growing [11,[26][27][28].…”

Safety challenges and safety measures of Li‐ion batteries

“…Improving the safety of the positive electrode material via materials science has been made by replacing the single crystal system of the original basic material, which can be achieved by synthesizing a more stable solid solution system via structural, chemical, or thermal approaches. 133 Improving the stability of the crystal structure at a large discharge depth can increase its usable capacity while improving the safety of the electrode. To this end, engineers and researchers have conducted many studies, which can be categorized into two approaches: surface modification and bulk doping.…”

Research Status and Analysis for Battery Safety Accidents in Electric Vehicles

“…(1) 美国阿贡国家实验室。阿贡国家实验室化 学科学与工程司联合阿贡国家实验室 X 射线科学 部、橡树岭国家实验室、阿尔伯克基桑迪亚国家实 验室在电池过充电技术领域开展了大量工作，取得 了相当丰富的研究成果。其中，RAGO 等系统地研 究了过充电行为对锂离子电池的影响，通过扫描电 子显微镜和能量分散光谱进行表征， 显示了从 120% 荷电状态(State of charge, SOC)时树突出现，并检测 到了过渡金属 [23] ，另外在阳极中发现了阴极金属， 在 140%SOC 以上观察到了 Li 损失，通过阴极电解 质反应观察到一层薄的富碳和富氧层形成 [24] 。同时 阿贡国家实验室深入探究了为电池提供过充电保护 的方法，CHEN 和 AMINE 等指出氧化还原穿梭剂 作为一种电解质添加剂，可以用作过充保护机制， 提高锂离子电池的安全性，对防护锂离子电池在运 行中的热失控至关重要，同时也对电池制造和维修 时的容量自动平衡很重要 [25] 。ZHANG 等 [26] 研究了 一种稳定的氧化还原穿梭分子 Bodma，可以提供超 过 120 个周期的过充电保护。…”