Boosting Manganese Selenide Anode for Superior Sodium-Ion Storage via Triggering α → β Phase Transition.

Chong, Shaokun; Li, Ting; Qiao, Shuangyan; Yang, Yi-Chun; Liu, Zhengqing; Yang, Jing; Tuan, Hsing-Yu; Cao, Guozhong et al. · ACS Nano · 2024

basic_science · Level V

Where this comes from

Abstract

Sodium-ion batteries (SIBs) have been extensively studied owing to the abundance and low-price of Na resources. However, the infeasibility of graphite and silicon electrodes in sodium-ion storage makes it urgent to develop high-performance anode materials. Herein, α-MnSe nanorods derived from δ-MnO<sub>2</sub> (δ-α-MnSe) are constructed as anodes for SIBs. It is verified that α-MnSe will be transferred into β-MnSe after the initial Na-ion insertion/extraction, and δ-α-MnSe undergoes typical conversion mechanism using a Mn-ion for charge compensation in the subsequent charge-discharge process. First-principles calculations support that Na-ion migration in defect-free α-MnSe can drive the lattice distortion to phase transition (alpha → beta) in thermodynamics and dynamics. The formed β-MnSe with robust lattice structure and small Na-ion diffusion barrier boosts great structure stability and electrochemical kinetics. Hence, the δ-α-MnSe electrode contributes excellent rate capability and superior cyclic stability with long lifespan over 1000 cycles and low decay rate of 0.0267% per cycle. Na-ion full batteries with a high energy density of 281.2 Wh·kg<sup>-1</sup> and outstanding cyclability demonstrate the applicability of δ-α-MnSe anode.