Stabilizing Interfacial Reactions for Stable Cycling of High?Voltage Sodium Batteries

Developing advanced electrolytes is critical for stabilizing electrode/electrolyte interfacial reactions and thus extending cycling stability of sodium (Na) batteries, especially when a high-voltage cathode (such as NaNi0.68Mn0.22Co0.10O2 (NaNMC)) used to achieve high energy density in batteries. Here, an electrolyte based on bis(fluorosulfonyl)imide (NaFSI)–triethyl phosphate, which highly stable against cathode, enabling long-term reported. Na||NaNMC cells with this demonstrate 89% capacity retention after 500 cycles cutoff voltage 4.2 V versus Na/Na+. A full cell hard carbon||NaNMC also exhibits good 83.5% 200 cycles. Postmortem analyses the cycled electrodes reveal that stabilization can be attributed formation interphase layer. The generated mainly by salt decomposition, suppresses transition metal dissolution surface reconstruction cathode. optimized minimize solid avoid loss. This study offers feasible pathway extended batteries guide further improvements performance manipulating chemistry properties.