Sea cucumber-inspired multi-phase metal sulfides with hierarchical structure towards energy storage with promoted safety

The usage of lithium ion batteries (LIBs) and sodium ion batteries (SIBs) have been challenged by the absence of suitable Li⁺/Na⁺ reservoirs. In this regard, a sea cucumber-inspired multi-phase metal sulfides with hierarchical structure (Bi₂S₃@C@CoS₂) is developed. When used in LIBs, Bi₂S₃@C@CoS₂ electrode shows an original discharge capacity of 1226.4 mAh g⁻¹, which remains at 1059.1 mAh g⁻¹ even after 229 cycles. When used in SIBs, this electrode shows an original discharge capacity of 750.4 mAh g⁻¹, with an exceedingly-low capacity deterioration ratio of 0.008 % per cycle during long-term cycling at 2 A g⁻¹. Comparisons with reported metal sulfides reveals the comparable or superior rate property of Bi₂S₃@C@CoS₂, stemming from its favorable Li⁺/Na⁺ storage actions kinetics. Of note, using Bi₂S₃@C@CoS₂ electrode promotes the thermal safety, via delaying the emerging of maximum thermal runaway temperature. This contribution may be encouraging for developing hierarchical metal sulfides towards favorable and safe energy storage.