Ultrahigh-Rate and Ultralong-Duration Sodium Storage Enabled by Sodiation-Driven Reconfiguration

摘要

Despite their variable valence and favorable sodiation/desodiation potential,vanadium sulfides (VS_x) used as anode materials of sodium-ion batteries(SIBs) have been held back by their capacity decline and low cyclingcapability, associated with the structure distortion volume expansion andpulverization. This study reports an accessible process to tackle thesechallenges via fabricating a 3D-VS_x anode for SIBs with ultrahigh-rate andultralong-duration stable sodium storage. The sodiation-driven reactivationof micro-nano 3D-VS_x activates the reconfiguration effect, effectively maintainingstructural integrity. Interestingly, the mechanical degradationof 3D-VS_x over the sodiation process can be controlled by fine-tuning theoperating voltage. The self-reconfigured open nanostructures with largevoid space not only effectively withstand repetitive volume changes andmitigate the damaging mechanical stresses, but also in turn construct aself-optimized shortened ion diffusion pathway. Moreover, the sodiationdrivenreconfiguration excites many active sites and optimizes a stablesolid-electrolyte interface, thereby delivering a reversible capacity of961.4 mA h g~(?1) after 1500 cycles at a high rate of 2 A g~(?1). This work providesnew insight into the rational design of electrodes toward long-lived SIBsthrough sodiation-driven reconfiguration.