Affiliation:
1. College of Chemical Engineering Fuzhou University Fuzhou 350116 China
2. Institute of Applied Physics and Materials Engineering University of Macau Macau 999078 China
3. School of Materials Science and Engineering State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou 310027 China
4. Qingyuan Innovation Laboratory Quanzhou 362801 China
Abstract
AbstractThe plateau‐type sodium titanate with suitable sodiation potential is a promising anode candidate for high safe and high energy density of sodium‐ion batteries (SIBs). However, the poor initial Coulombic efficiency (ICE) and cyclic instability of sodium titanate are attributed to the unstable interfacial structure along with the decomposition of electrolytes, resulting in the continuous formation of solid electrolyte interface (SEI) film. To address this issue, a chemical grafting method is developed to fabricate a highly stable interface layer of inert Al2O3 on the sodium titanate anode, rendering the high ICE and excellent cycling stability. Based on theoretical calculations, NaPF6 are more likely adsorption on the Al2O3 surface and produce sodium fluoride. The formation of a thin and dense SEI film with rich sodium fluoride achieves the low interfacial resistances and charge‐transfer resistances. Benefitting from our design, the obtained sodium titanate exhibits a high ICE from 67.7 % to 79.4 % and an enhanced reversible capacity from 151 mAh g−1 to 181 mAh g−1 at 20 mA g−1, along with an increase in capacity retention from 56.5 % to 80.6 % after 500 cycles. This work heralds a promising paradigm for rational regulation of interfacial stability to achieve high‐performance anodes for SIBs.
Funder
National Key Research and Development Program of China