Synthesis of Vacancy-Rich NiTex-NC Catalyst under Mild Conditions for High-Performance Lithium Sulfur Batteries

Abstract

Due to the slow conversion kinetics of polysulfides, the practical application of lithium–sulfur batteries faces significant challenges. Transition metal tellurides exhibit good catalytic activity and are expected to help mitigate the shuttle effect in lithium–sulfur batteries. Vacancies, as a form of defect, can further enhance the conductivity and catalytic activity of the catalysts. However, most vacancy creation is achieved by the action of strong reducing agents (such as H₂, NaBH₄, hydrazine, etc.). Here, we utilized the similarity in lattice parameters between NiTe and NiTe₂ to adjust the extent of lattice contraction in NiTe₂ by controlling the Te powder content, ultimately obtaining a Te-vacancy-rich NiTe_x-NC catalyst under mild conditions. The unsaturated coordination between Ni and Te provides abundant active sites for the chemical adsorption and catalytic conversion of polysulfides, thus allowing NiTe_x-NC to significantly lower the reaction energy barrier of polysulfides and effectively inhibit the shuttle effect. The results show that NiTe_x-NC can achieve a specific capacity of 589.4 mAh g^–1 at a rate of 7 C, and after 1000 cycles at 2 C, the capacity decay per cycle is only 0.0278%. Even under complex conditions (with a sulfur loading of 7.5 mg cm^–2 and a liquid sulfur ratio of 10 μL mg^–1), it still maintains good cycling stability.