Facile synthesis of tin phosphide/reduced graphene oxide composites as anode material for potassium-ion batteries

Potassium-ion batteries (PIBs) have been attractedattention in grid-scale energy storage owning to the earth-abundance and low cost. However, the progresses in PIBs chemistry have so far been hindered bylacking suitable electrode materials to host the relatively large K+ ions. Herein, we report tin phosphide/reduced graphene oxide (Sn4P3/RGO) composites used as anode material for PIBs,which was prepared via a high-energy ball-milling process. The coexistence of small Sn4P3 nanoparticles and RGO nanosheets endows the composites with improved electronic conductivity, highly structural integrity and superior electrochemical performance. When used as anode material for PIBs, a high reversible capacity of 452.6 mAh g(-1) at 80 mA g(-1), superior rate capability of 116.4 mAh g(-1) at high current density of 800 mA g(-1), and still remains 157.3 mAh g(-1) at 600 mA g(-1) after 60 cycles. This work provides experimental guideline to develop suitable and advanced anode materials for PIBs.