Hierarchically porous carbon supported Sn4P3 as a superior anode material for potassium-ion batteries

As a promising alternative to lithium-ion batteries (LIBs), the state-of-art potassium-ion batteries (PIBs) are attracting increasing attentions owing to the abundance and low cost of potassium. However, development of practical electrode materials for PIBs is still in its early stage and the related mechanisms are still unclear. In this work, hierarchically porous carbon supported Sn4P3@C composite prepared through a low temperature solvothermal method is firstly reported as anode material for PIBs. The electrode delivers a high discharge capacity of 473.3 mAh g−1 at 50 mA g−1 and superior rate capability of 183.6 mAh g−1 at 2.0 A g−1, surpassing most of the reported anode materials. Besides, the Sn4P3@C electrode can maintain a high reversible capacity of 181.5 mAh g−1 after 800 cycles at a high current density of 500 mA g−1. Moreover, in-depth characterizations such as GITT (Galvanostatic Intermittent Titration Technique), ex-situ XRD/HRTEM and consecutive CV (Cyclic Voltammetry) measurements are conducted to reveal the mechanisms involved in the potassiation/de-potassiation repeats.