Reconciling Capacity Degradation for Sodium-Ion Pouch Cell by Practical Electrocatalytic-Driven Compensation Strategy.

Li, Jianguo; Dong, Youzhong; Wang, Xin; Li, Yunbo; Fan, Qinghua; Xu, Jiantie; Xie, Haijiao; Kuang, Quan et al. · ACS Nano · 2025

basic_science · Level V

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Abstract

Irreversible active sodium loss (ASL) is widely regarded as a pivotal factor influencing the cycle life and energy density of sodium-ion full cells. Introducing practical electrocatalyst-driven compensation strategies for ASL and other multiple benefits in sodium-ion batteries (SIBs) is a tireless pursuit of researchers. Herein, Pd atoms were used to catalytically drive the decomposition of Na<sub>2</sub>O to compensate for ASL in Na<sub>3</sub>(Mn<sub>0.8</sub>Fe<sub>0.2</sub>)<sub>2</sub>(PO<sub>4</sub>)(P<sub>2</sub>O<sub>7</sub>)//hard carbon (NMFPP//HC) pouch cells. This compensation strategy not only replenished the sodium inventory loss caused by SEI and Mn<sup>2+</sup> shuttle effect but also constructed a NaF-rich rigid CEI layer. The dissolution and shuttling of Mn<sup>2+</sup> can be significantly inhibited by this kind of rigid NaF-CEI layer. Finally, incorporating 8 wt % currently modified precondition with NMFPP cathode, the energy density of the corresponding pouch cell (NMFPP-PNO//HC) presents an essential improvement of 29% relative to the unmodified system. This study proposes a universal approach for ASL compensation and electrode stabilization in the design of high-performance SIBs.