Two dimensional MnPSe₃ layer stacking composites with superior storage performance for alkali metal-ion batteries

Two-dimensional MnPSe₃ Van der Waals stacked in an ABC sequence has abundant and low-cost Mn resources, but has yet to exhibit expected performance as an electrode material in battery devices. Here, we report a 2D/2D composite consisting of few layer MnPSe₃ nanosheets and graphite through a high energy ball milling method for uses on the anodes alkali metal-ion batteries, including lithium ion battery (LIB) and potassium ion battery (PIB). These unique 2D/2D layer nanostructures, with MnPSe₃ layers hierarchically stacked in graphite, can successfully overcome the severe aggregation due to restacking during charge/discharge cycles. Moreover, density functional theory (DFT) calculations show that the band gap of the MnPSe₃/graphite hybrid is as low as 0.07 eV, confirming that the combination of MnPSe₃ and graphite efficiently reduces the ion migration energy barrier. As a result, MnPSe₃/graphite stacking composites achieve a discharge capacity of 488.1 mA h g^-1 after 500 cycles at 2000 mA g^-1 in LIB, and 236.7 mA h g^-1 after 700 cycles at 250 mA g^-1 in PIB. Moreover, the analysis of electrochemical, kinetics, reactions mechanism, DFT, and full cell applications were investigated deeply. This work strongly supports the possibility of MnPSe₃/graphite hybrid as a promising candidate for alkali ion batteries, and makes important improvements for the application of two-dimensional MPCh₃ layer materials in storage systems.