Bimetallic alloy Fe Co1-PS3 with boosted lithium reaction kinetics for lithium-ion batteries

Metal phosphorous trisulfide (MPS3) is considered to be the promising anode material for LIBs owing to the advantage of its high capacity and layered structure. Nevertheless, the inferior reaction kinetics resulting from its low electron conductivity hinder its further practical application. Herein, bimetallic alloy FexCo1-xPS3 with gradient Fe: Co coated by a nitrogen-doped carbon layer is designed to accelerate the electron transfer and Li-ion diffusion rate. The in-situ X-ray diffraction technique is applied to precisely confirm the phase evolution of the Fe0.63Co0.37PS3 coated by N-doped carbon layer (FCPS-5/NC) anode upon the (de)lithiation process. Theoretical calculations confirm that alloying with Co can reduce the bandgap and decrease the energy barrier of Li ion diffusion. In addition, the conductive carbon layer can improve the electric conductivity of the whole electrode. As an anode for LIBs, the FCPS-5/NC electrode reveals a high rate capacity of 554 mA h g−1 at 3.0 A/g and thus achieves a comparable lithium storage performance among the reported MPS3-based anodes. Meanwhile, the Li-ion full cell assembled with FCPS-5/NC anode also exhibited excellent cycling performance, confirming its value for practical application. This work demonstrates a brand-new strategy to prepare advanced MPS3-based materials for superior LIBs.