材料科学
电解质
阴极
煅烧
锂(药物)
化学工程
容量损失
涂层
磷酸铁
锂钴氧化物
复合数
磷酸盐
氧化钴
铝
氧气
锂离子电池
离子
氧化物
自行车
电池(电)
电极
纳米技术
复合材料
冶金
催化作用
化学
有机化学
考古
功率(物理)
物理化学
内分泌学
工程类
物理
历史
医学
量子力学
生物化学
作者
Xiao Wang,Qian Wu,Siyuan Liu,Zheming Tong,Duo Wang,Houlong Zhuang,Xinyang Wang,Yingying Lü
标识
DOI:10.1016/j.ensm.2021.01.031
摘要
Lithium cobalt oxide (LCO), a promising cathode with high compact density around 4.2 g cm−3, delivers only half of its theoretical capacity (137 mAh g−1) due to its low operation voltage at 4.2 V (vs. Li/Li+) under commercial conditions. To improve its practical capacity, higher cut-off voltages are often adopted, which result in severe structure destruction and cause side reactions with electrolyte. The safety concerns of oxygen release further restrict the application of LCO. Here, we achieve stable cycling of LCO at 4.6 V (vs. Li/Li+) through a surface engineering strategy by using lithium-aluminum-phosphate composite coating materials. This strategy prevents direct contact between cathode and electrolyte, reducing the loss of active materials without hindering the lithium ion migration. After calcination, a doping layer (or solid solution) includes phosphorus and aluminum is formed, which helps maintain the surface structure and stabilize the oxygen atoms around particle surface and shows high ion mobility when operated at 4.6 V (vs. Li/Li+). All these benefits synergistically contribute to the stable cycling of LCO at 4.6 V (vs. Li/Li+) with high capacity retentions of 88.6% (30°C) and 78.6% (45°C), respectively, after 200 cycles.
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