Synthesis of Vacancy-Rich NiTe_<i>x</i>-NC Catalyst under Mild Conditions for High-Performance Lithium Sulfur Batteries

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_<i>x</i>-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_<i>x</i>-NC to significantly lower the reaction energy barrier of polysulfides and effectively inhibit the shuttle effect. The results show that NiTe_<i>x</i>-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.