Strain Engineering of Layered Heterogeneous Structure via Self-Evolution Confinement for Ultrahigh-Rate Cyclic Sodium Storage

To get a robust architecture for rapid and permanent ion insertion/extraction, various frameworks are constructed, attempting to enhance the high-rate lifespan. However, uncontrollable structural evolution always results in the structural failure derived from the continuous increasing inner strain during the cycling. Herein, inspired by the nest structure, a stable framework with wave-like surface morphology and cross-linked inner configuration is fabricated, which possesses fast ion migration channel and stable structure. Most importantly, the concept of synchronous self-evolution confinement is proposed for high-capacity conversion-type anode materials, which can control the aggregated inner strain and alleviate the inescapable electrode pulverization, thus ensuring the electrode stability and boosting the structure integrity during the repeated cycling. When serving as an anode for sodium ion batteries, the initial nest-like (SnFe)S-2 heterogeneous mildly evolves into a stable architecture with exceptional performance, expressing a prominent rate property (389.4 mA h g(-1) at 30 A g(-1)) and stable durability (627.41 mA h g(-1) at 10 A g(-1) for 800 cycles). Significantly, this route of strain engineering sheds significant light on solving large volume-expansion-type materials for high reversible capacity, especially in the exploration of electrochemical energy storages.