Boosting Reversibility of Mn-Based Tunnel-Structured Cathode Materials for Sodium-Ion Batteries by Magnesium Substitution.

ABSTRACT: Electrochemical irreversibility and sluggish mobility of Na⁺ in the cathode materials result in poor cycle stability and rate capability for sodium-ion batteries. Herein, a new strategy of introducing Mg ions into the hinging sites of Mn-based tunnel-structured cathode material is designed. Highly reversible electrochemical reaction and phase transition in this cathode are realized. The resulted Na_0.44Mn_0.95Mg_0.05O₂ with Mg²⁺ in the hinging Mn-O₅ square pyramidal exhibits promising cycle stability and rate capability. At a current density of 2 C, 67% of the initial discharge capacity is retained after 800 cycles (70% at 20 C), much improved than the undoped Na_0.44MnO₂. The improvement is attr

SUBMITTER: Li XL 

PROVIDER: S-EPMC8097362 | biostudies-literature | 2021 May

REPOSITORIES: biostudies-literature