【摘要】 通过对常温不同放电倍率的18650型锂离子蓄电池循环性能的测试表明,2C高倍率循环的锂离子蓄电池,300次容量衰减率为18.8%,而1C和0.5C放电倍率循环的电池容量衰减率分别为14.2%和10.5%。高倍率循环的Li-CoO2/石墨系锂离子蓄电池容量衰减严重。X射线衍射法(XRD)、透射电子显微镜法(TEM)、扫描电子显微镜法(SEM)分析表明,循环后的正极材料结构有明显的改变,负极表面膜增厚,导致Li+数量的减少及扩散通道阻塞,是引起锂离子蓄电池容量衰减的基本原因。更多还原

【Abstract】 Capacity fade of 18650-type lithium-ion batteries cycled with different discharge rates were tested at ambient temperature.At 2 C discharge rate,the capacity decays were 18.8% of the initial capacity after 300 cycles.At 1 C and 0.5 C discharge rate,the capacity decays were only 14.2% and 10.5%,respectively.It is indicated that the capacity fade was faster at high rate cycling.Before and after cycling,cathode and anode electrode materials had been examined by using XRD,TEM and SEM.The results showed that an obvious change in the structure of the LiCoO2 was found and SEI precipitation layer at the surface of anode particles became thicker,resulting in the capacity fade of the lithium-ion battery.更多还原