摘要
采用脉冲激光沉积法制备了NiCo_2S_4薄膜,利用恒流充放电和循环伏安测试研究了NiCo_2S_4薄膜作为锂离子电池负极材料的电化学性能和充放电机理。采用高分辨电子显微镜和选区电子衍射(TEM&SAED)表征了NiCo_2S_4薄膜首次循环过程中的组成与结构变化。恒流充放电测试结果显示NiCo_2S_4薄膜在3μA·cm-2的放电电流下,0~3 V(vs Li+/Li)范围内,薄膜的首次放电容量为698 m Ah·g^(-1),经过200次循环之后的放电容量为365 m Ah·g^(-1);在循环伏安测试中得到了分步反应的可逆氧化还原峰。TEM和SAED分析结果揭示了NiCo_2S_4薄膜与Li的电化学反应机理:首次放电过程中NiCo_2S_4与Li发生转化反应生成了Li_2S、Ni和Co,充电后生成了CoS和NiS复合薄膜。后续循环为CoS和NiS复合薄膜的可逆分解与形成。研究表明NiCo_2S_4是一种有潜在应用价值的锂离子电池负极材料。
NiCo_2S_4 thin films have been successfully prepared by pulsed laser deposition. The structural,electrochemical properties and reaction mechanism of the NiCo_2S_4 thin film anodes for lithium ion batteries have been investigated by transmission electron microscopy（TEM）, selected-area electron diffraction measurements（SAED）, the charge/discharge measurements and cyclic voltammetry（CV）. The charge/discharge results suggested that in the range of 0~3.0 V（vs Li＋/Li）, the reversible discharge capacity was 698 m Ah·g^（-1） at a current density of3 μA·cm^（-2）. After 200 cycles, the discharge capacity was 365 m Ah·g^（-1）. Multistep reactions are revealed by the CV data of NiCo_2S_4 thin films. Ex situ TEM results showed that NiCo_2S_4 could react with Li to form Li_2S, Co and Ni during initial discharging and Ni S and Co S formed upon charging. The reversible electrochemical reacting occurred between NiS, CoS and Li_2S, Co, Ni during the following cycles. NiCo_2S_4 was believed to be a promising anode material for rechargeable lithium batteries due to its good cycle performance.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2015年第12期2331-2336,共6页
Chinese Journal of Inorganic Chemistry
基金
中国工程物理研究院科学技术基金(No.2013A0302014)
中国工程物理研究院超精密加工技术重点实验室基金(No.ZZ13007)资助项目
