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

An Sodium Bis(trifluoromethanesulfonyl)imide-based Polymer Electrolyte for Solid-State Sodium Batteries

采用简单的溶液浇铸法制备出由双(三氟甲基磺酰)亚胺钠(Na TFSI)/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,Na TFSI/PEO([EO]/[Na+]=15)SPE具有相对高的电导率(σ≈10^(-3)S·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Na TFSI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|NaCu_(1/9)Ni_(2/9) Fe_(1/3) Mn_(1/3)O_2电池中展现出良好的循环和倍率性能。

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^-3 S·cm^-1） at 80 ℃, excellent electrochemical stability （4.86 V vs. Na^＋/Na）, and thermal stability up to 350 ℃. 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/gFe1/3Mn1/3O2 cell.