Boosting Cycling Stability of Polymer Sodium Battery by "Rigid-Flexible" Coupled Interfacial Stress Modulation.

Pan, Jun; Xu, Shumao; Cai, Tianxun; Hu, Lulu; Che, Xiangli; Dong, Wujie; Shi, Zhiyuan; Rai, Alok Kumar et al. · Nano Lett · 2023

basic_science · Level V

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Abstract

The discontinuous interfacial contact of solid-state polymer metal batteries is due to the stress changes in the electrode structure during cycling, resulting in poor ion transport. Herein, a rigid-flexible coupled interface stress modulation strategy is developed to solve the above issues, which is to design a rigid cathode with enhanced solid-solution behavior to guide the uniform distribution of ions and electric field. Meanwhile, the polymer components are optimized to build an organic-inorganic blended flexible interfacial film to relieve the change of interfacial stress and ensure rapid ion transmission. The fabricated battery comprising a Co-modulated P2-type layered cathode (Na<sub>0.67</sub>Mn<sub>2/3</sub>Co<sub>1/3</sub>O<sub>2</sub>) and a high ion conductive polymer could deliver good cycling stability without distinct capacity fading (72.8 mAh g<sup>-1</sup> over 350 cycles at 1 C), outperforming those without Co modulation or interfacial film construction. This work demonstrates a promising rigid-flexible coupled interfacial stress modulation strategy for polymer-metal batteries with excellent cycling stability.