Failure analysis with a focus on thermal aspect towards developing safer Na-ion batteries
Li Yuqi1, 2, Lu Yaxiang1, 3, †, Chen Liquan1, 2, 3, Hu Yong-Sheng1, 2, 3, ‡
       

(a) Three stages of the thermal runaway process.[9] (b)–(e) The safety test results of the prototype pouch cells (Na0.9[Cu0.22Fe0.30Mn0.48]O2//pyrolyzed anthracite) at fully charged state. The voltage and temperature evolutions in the processes of (b) external short-circuit test, (c) overcharge test, and (d) nail penetration test; (e) the photographs of pouch cells before and after safety tests.[10]