High mixing entropy of MnFeCoNiCu-S to drive high performance sodium storage

Transition metal sulfides (TMSs) are often used as anode materials in sodium-ion batteries (SIBs). Nevertheless, the inevitable volume effect and low intrinsic conductivity cause rapid capacity fading of the TMS anode materials. In our work, a high-entropy metal sulfide (HEMS) MnFeCoNiCu-S anode material was obtained by vulcanization and pyrolysis of quinary MOF precursors. Mixing of multiple cations contributes to the diversity of material chemistry and structure. Strong synergies between Mn, Fe, Co, Ni, and Cu establish a steady electronic structure, and high configurational entropy gives the material excellent mechanical strength and excellent stability. Furthermore, the derived carbon matrix can also improve the conductivity and cycling stability of the HEMS. At a current density of 5 A g^-1, the HEMS anode can still provide 326.4 mA h g^-1 capacity after 7000 cycles, showing long-term sodium storage durability. The synergies of multiple metals and the transfer of multiple electrons ensure excellent sodium storage, which makes the HEMS a favorable candidate for SIB anode materials.