Engineering hierarchical structure of multi-phase metal sulfides with doped carbon protector towards superb energy storage

The progressively improving technologies and products have proposed higher requirements for energy storing devices with cheapness and sustainability. Hence, the rechargeable batteries of lithium ion batteries (LIBs) and sodium ion batteries (SIBs) have been preferred. Nevertheless, the extended usages of LIBs and SIBs are confronted with the dilemma of lacking suitable Li⁺/Na⁺ reservoirs. In this way, a hierarchical structure (Co-Ni-S@NSC) of multi-phase metal sulfides with heteroatoms doped carbon protector is rationally designed, which shows relatively-high specific surface area and high proportions of pyridinic-N as well as pyrrolic-N. When used as LIBs anode, Co-Ni-S@NSC electrode delivers a high discharge capacity of 1440.2 mA h g⁻¹, along with high stability. Meanwhile, this electrode shows superior rate capability than many reported metal sulfides. When utilized as SIBs anode, a correspondingly-high capacity of 788.3 mA h g⁻¹ is found for Co-Ni-S@NSC, which presents high CE above 97.0% during whole cycling. Additionally, the contrast with previous works proves its strengths in rate performance. Briefly, this electrode possesses favorable Li⁺/Na⁺ storage properties, stemming from the synergy of heteroatoms doping, relatively-high specific surface area and multi-phase metal sulfides design. This work may shed a light on constructing multi-phase metal sulfides based hierarchical structure as high-performance Li⁺/Na⁺ hosts.