Silver boosts ultra-long cycle life for metal sulfide lithium-ion battery anodes: Taking AgSbS₂ nanowires as an...

Metal sulfide, being a high-capacity anode material, is a promising anode material for rechargeable lithium-ion batteries (LIBs). However, most research efforts have focused on improving their low cycling performance due to multiple combined factors, including low conductivity, huge volume changes, multi-step conversion/alloying reactions, and redox shuttling effect, during the cycling process. Here, we report that by using AgSbS₂ nanowires as LIB anode materials, a record-breaking long cycle life metal sulfide anode has been achieved through the silver synergistic electrochemical performance effect. We found that while the AgSbS₂ nanowire anode is cycled, Ag precipitated out to form a nanocrystal tightly connected with Sb and S and plays a key role in highly-reversible electrochemical performance. Ag can effectively enhance the electrode conductivity, increase ion diffusion rate, serve a diluent huge volume changes during conversion-alloying reactions, improve the absorbability and catalytic ability towards LiPSs to reduce shutting effect of sulfur, and enhanced Li⁺ adsorption. As a result, AgSbS₂ nanowire anodes maintain 90% capacity retention over 5000 and 7000 cycles at the current densities of 500 mA g^-1 and 2000 mA g^-1, respectively, whereas the capacities of Sb₂S₃ nanowire and Sb₂S₃/C nanowire anodes drop rapidly within 10 cycles. The ultra-stable cycle life is superior to the state-of-the-art metal sulfide anodes. Finally, using AgSbS₂ nanowires as the anode combined with the cathode LiNi₅Co₃Mn₂, a full battery after 480 cycles was assembled to verify that its stability (high retention rate of 99.5%) can be used in the current commercial battery architecture. This work solves multiple problems related to shuttling effects and complex reactions of metal sulfide anodes, and provides important progress for the future development of metal sulfide anodes for LIBs.