“Lasagna”‐Structured SnS‐TaS2 Misfit Layered Sulfide for Capacitive and Robust Sodium‐Ion Storage

Abstract

AbstractStannous sulfide (SnS), a conversion‐alloying type anode for sodium‐ion batteries, is strong Na+ storage activity, a low voltage platform, and high theoretical capacity. However, grain pulverization induced by intolerable volume change and phase aggregation causes quick capacity degradation and unsatisfactory rate capability. Herein, a novel “lasagna” strategy is developed by embedding a SnS layer into the interlayer of an electrochemically robust and electron‐active TaS2 to form a misfit layered (SnS)1.15TaS2 superlattice. For Na+ storage, the rationally designed (SnS)1.15TaS2 anode exhibits high specific capacity, excellent rate capability, and robust cycling stability (729 mAh cm−3 at 15 C after 2000 cycles). Moreover, the as‐assembled (SnS)1.15TaS2 || Na3V2(PO4)3 full cells achieve robust and fast Na+ storage performance with ≈100% capacity retention after 650 cycles at 15 C, which also demonstrates good low‐temperature performance at −20 °C with a capacity retention of 75% and 2 C high‐rate charge/discharge ability.