纳米CoSe的合成及其在醚类电解液中的电化学性能

Synthesis of nano CoSe and electrochemical properties in ether electrolytes

基于转化反应的硒化钴由于其层状结构和高的比容量而备受关注,然而有效抑制不可逆的Se溶解和在循环过程中严重的体积变化引起的快速容量衰减仍然是一个挑战.通过水热法合成纳米级CoSe材料,合适的纳米结构可以有效地改善电池的性能(钠离子电池在0.1 A/g电流密度下,进行100次循环后,具有413 mA·h/g的超高容量).与酯基电解液不同,选择的醚基电解液避免了酯基电解液和多硒化物反应消耗活性材料,进而引起容量衰减的问题,最终可以实现更稳定的循环周期(钠离子电池在2 A/g电流密度下,进行600次循环后,具有303 mA·h/g的超高容量).

Cobalt selenide based on conversion reaction has attracted much attention due to its layered structure and high specific capacity.However,it is still a challenge to effectively suppress irreversible Se dissolution and rapid capacity decay caused by serious volume changes during the cycle.Here,the nano-scale CoSe material was synthesized by hydrothermal method and the proper nanostructures was found to effectively improve performance of the battery.The results show that the discharge specific capacity of sodium-ion battery stabilizes at 413 mA·h/g after 100 cycles under the current density of 0.1 A/g.Unlike ester-based electrolytes,the selected ether based electrolyte avoids the reaction between ester-based electrolyte and selenide,which consumes active materials and causes capacity decay.Finally,a more stable cycle can be achieved,and it shows that discharge specific capacity of sodium-ion batter stabilized at 303 mA·h/g after 600 cycles under the high current density of 2 A/g.