溶剂化
电解质
材料科学
溶剂化壳
电子转移
阴极
钠
离子
密度泛函理论
功率密度
分子
化学物理
电极
化学
物理化学
计算化学
热力学
物理
有机化学
功率(物理)
冶金
作者
Xiaoyi Yang,Chao Peng,Minjie Hou,Da Zhang,Bin Yang,Dongfeng Xue,Yong Lei,Feng Liang
标识
DOI:10.1002/adfm.202201258
摘要
Abstract In sodium–air batteries (SABs), achieving the regulation of the electron transfer number during oxygen reduction reactions (ORRs) in the same electrolyte system remains a significant challenge. In this work, a promising strategy is proposed to dynamically modulate 2e − /4e − transfer in ORRs by regulating the electrolyte structures to realize the different performances of SABs. The 4e − ORR can be realized by decreasing the electrolyte concentration. The solvation sheath of Na + at dilute concentrations consists mainly of water molecules that hinder the access of Na + to the cathode surface due to the high solvation energies indicated by theoretical calculations, thereby impeding the 2e − reaction. In contrast, excess free water can easily access the cathode surface and trigger the 4e − ORR. The solvation energies of Na + can be remarkably reduced by increasing the electrolyte concentration, forming a water‐in‐salt unit, in which the Na + mainly coordinates with the bis(fluorosulfonyl)imide anion and can be easily released from the solvation sheath. Hence, the 2e − ORR is significantly promoted and becomes the dominant reaction. The SAB based on the 2e − reaction exhibits excellent energy density (15980 Wh kg −1 ) and good cycle performance (300 times), and the 4e − reaction exhibits excellent power density (12.09 mW cm −2 ).
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