Rhenium Diselenide Anchored on Reduced Graphene Oxide as Anode with Cyclic Stability for Potassium-Ion Battery

An effective route is developed to fabricate ultrathin rhenium diselenide (ReSe2) nanosheets anchored on reduced graphene oxide (rGO) nanoflakes (ReSe2@rGO). When the ReSe2@rGO is used as an anode material in the potassium-ion batteries (PIBs), the graphene offers a conductive matrix to buffer the volume alteration during repeated K+ insertion/extraction cycles. The stable interfacial connection between ReSe2 and graphene greatly promotes the integration of the active ReSe2 nanosheets, preventing their agglomeration. At the same time, these ultrathin nanosheets shorten the ion/electron diffusion path, leading to stable cyclic performance. As a result, the ReSe2@rGO anode enhances the electrochemical performance of the as-synthesized PIB with a high specific capacity of over 250 mAh g(-1) at a current density of 500 mA g(-1) even after 200 cycles. Excellent rate performance and lengthy cyclic performance with 150 mAh g(-1) at 2 A g(-1) are also observed even after 500 cycles.