双(三氟甲基磺酰)亚胺钠基聚合物电解质在固态钠电池中的性能

摘要

A solid polymer electrolyte (SPE), composed of sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) and poly(ethylene oxide) (PEO), is prepared by a simple solution-casting method. The physicochemical and electrochemical properties of the NaTFSI/PEO ([EO]/[Na+] = 15) SPE in terms of its phase transitions, crystallization, thermal stability, ionic conductivity, and anodic electrochemical stability are systematically investigated. We demonstrate that the NaTFSI/PEO SPE has a relatively high ionic conductivity (σ ≈ 10?3S·cm?1) at 80 °C, excellent electrochemical stability (4.86 V vs. Na+/Na), and thermal stability up to 350 °C. More importantly, the NaTFSI-based SPE delivers not only excellent chemical and electrochemical stability with sodium metal, but also good cycling and rate performances in an Na|SPE|NaCu1/9Ni2/9Fe1/3Mn1/3O2cell.%采用简单的溶液浇铸法制备出由双(三氟甲基磺酰)亚胺钠(NaTFSI)/聚氧乙烯(PEO)构筑的固态聚合物电解质(SPE),并针对其相转变、结晶性、热稳定性、电导率以及电化学稳定性等基础理化及电化学性质进行了系统表征.结果表明,NaTFSI/PEO([EO]/[Na+]=15)SPE具有相对高的电导率(σ≈10?3S·cm?1,80°C)、高的耐氧化能力(4.86 V vs Na+/Na)和热稳定性高达350 °C.电池测试结果表明,该NaTFSI基SPE不仅对金属钠电极能够呈现出优异的界面稳定性,而且在Na|SPE|NaCu1/9Ni2/9Fe1/3Mn1/3O2电池中展现出良好的循环和倍率性能.