无水层状钠锰氧正极材料的合成及其锂离子嵌入性能

摘要

Anhydrous layered sodium manganese oxides were synthesized by acetate sol-gel method and glycolic acid sol-gel method, respectively. The structure and performance of as-prepared materials were characterized by thermogravimetric analysis (TG), inductively coupled plasma (ICP), X-ray diffractometer (XRD), scanning electron microscope (SEM), galvanostatic charge/discharge and cyclic voltammetry (CV). The results show that the sample a-Na0.65MnO2.13 synthesized by glycolic acid sol-gel method has much better electrochemical performances than that of a-Na0.67MnO2.26 prepared by acetate sol-gel method. Besides, a-Na0.65MnO2.13 exhibits the second discharge capacity of 182 mA-h/g at a current density of 25 mA/g in the cutoff voltage of 2.0-4.3 V, and the capacity retention after 40th cycle is close to 90.6%.%分别用醋酸盐溶胶凝胶法和乙醇酸溶胶凝胶法合成无水层状钠锰氧.用热重(TG动、等离子发射光谱(ICP)、X线衍射(XRD)、扫描电镜(SEM)、恒电流充放电测试和循环伏安(CV)等对材料的结构和性能进行研究.研究结果表明:乙醇酸溶胶凝胶法制备的样品α-Na0.65MnO2.13比醋酸盐溶胶凝胶法制备的样品α-Na0.67MnO2.26具有更好的电化学性能.在充放电电流密度为25 mA/g和电压为2.0～4.3V时,乙醇酸溶胶凝胶法制备的材料α-Na0.65-MnO2.13的第2次放电比容量达182 mA·h/g,40次循环后容量保持率达90.6％.