NixSy/N, S-codoped carbon (NSC) hollow microspheres derived from a novel metal organic porous polymer for high performance lithium ion batteries

Abstract

Addressing the challenges of volume expansion and polysulfide dissolution in transition metal sulfide (MxSy) anodes during the cycling process of lithium-ion batteries (LIBs) is crucial for their practical application. This work utilizes a novel organic ligand containing a thiol group, 5-mercapto-1-phenyl-1H-tetrazole (PTA), to design a series of metal-organic porous polymers, which are then derivatized into N, S co-doped MxSy@carbon encapsing materials. The PTA organic ligand not only serves as a dopants source of N and S but also undergoes in-situ sulfurization with metal to form MxSy nanoparticles coated with carbon. Particularly, the derived NixSy@carbon hollow microspheres feature a unique hollow spherical carbon structure that not only mitigates the volume expansion of nickel sulfide but also shortens the ion diffusion distance while providing a significant number of active sites in LIBs. The research also revealed that variations in crystal structures caused by temperature have a profound influence on the Li+ storage capabilities of the LIBs. When evaluated as anode materials for LIBs, the NiS1.03@NSC600 demonstrates excellent reversible specific capacity and good long-life cycling stability. After 700 charge/discharge cycles, the NiS1.03@NSC600 anode maintains a reversible specific capacity of 480.4 mAh g−1 at 1 A g−1. In addition, we also evaluated CuxSy@NSC and CoxSy@NSC as anode materials, both of which demonstrated excellent electrochemical performance.