法拉第效率
电化学
容量损失
电解质
电池(电)
材料科学
电极
阴极
降级(电信)
钠
化学工程
化学
功率(物理)
冶金
电气工程
热力学
工程类
物理化学
物理
作者
Yong-Kai Xu,Haozheng Sun,Cunshuang Ma,Jingjing Gai,Yanhua Wan,Weihua Chen
标识
DOI:10.1016/j.cjche.2021.08.020
摘要
The irreversible consumption of sodium in the initial several cycles greatly led to the attenuation of capacity, which caused the low initial coulombic efficiency (ICE) and obvious poor cycle stability. Pre-sodiation can effectively improve the electrochemical performance by compensating the capacity loss in the initial cycle. Here, carbon-coated sodium-pretreated iron disulfide (NaFeS2@C) has been synthesized through conventional chemical method and used in sodium metal battery as a cathode material. The calculated density of states (DOS) of NaFeS2@C is higher, which implies enhanced electron mobility and improved cycle reversibility. Because of the highly reversible conversion reaction and the compensation of irreversible capacity loss during the initial cycle, the Na/NaFeS2@C battery achieves ultra-high initial coulombic efficiency (96.7%) and remarkable capacity (751 mA·h·g−1 at 0.1 A·g−1). In addition, highly reversible electrochemical reactions and ultra-thin NaF-rich solid electrolyte interphase (SEI) also benefit for the electrochemical performance, even at high current density of 100 A·g−1, it still exhibits a reversible capacity of 136 mA·h·g−1, and 343 mA·h·g−1 after 2500 cycles at 5.0 A·g−1. This work aims to bring up new insights to improve the ICE and stability of sodium metal batteries.
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