Lithium Storage Performance Boosted via Delocalizing Charge in Zn_x Co_{1- x} PS₃ /CoS₂ of 2D/3D Heterostructure

A promising anode material consisting of bimetallic thiophosphate Zn_x Co_{1- x} PS₃ and CoS₂ with 2D/3D heterostructure is designed and prepared by an effective chemical transformation. Density functional theory calculations illustrate that the Zn²⁺ can effectively modulate the electrical ordering of Zn_x Co_{1- x} PS₃ on the nanoscale: the reduced charge distribution emerging around the Zn ions can enhance the local built-in electric field, which will accelerate the ions migration rate by Coulomb forces and provide tempting opportunities for manipulating Li⁺ storage behavior. Moreover, the merits of the large planar size enable Zn_x Co_{1- x} PS₃ to provide abundant anchoring sites for metallic CoS₂ nanocubes, generating a 2D/3D heterostructure with a strong electric field. The resultant Zn_x Co_{1- x} PS₃ /CoS₂ can offer the combined advantages of bimetallic alloying and heterostructure in lithium storage applications, leading to outstanding performance as an anode material for lithium-ion batteries. Consequently, a high capacity of 794 mA h g^-1 can be retained after 100 cycles at 0.2 A g^-1 . Even at 3.0 A g^-1 , a satisfactory capacity of 465 mA h g^-1 can be delivered. The appealing alloying-heterostructure and electrochemical performance of this bimetallic thiophosphate demonstrate its great promise for applications in practical rechargeable batteries.