MoSe<sub>2</sub>@CNT Core–Shell Nanostructures as Grain Promoters Featuring a Direct Li<sub>2</sub>O<sub>2</sub> Formation/Decomposition Catalytic Capability in Lithium‐Oxygen Batteries
Biao He, Gaoyang Li, Jiajia Li, Jun Wang, Hui Tong, Yuqi Fan, Weiliang Wang, Shuhui Sun, Feng Dang
Abstract
Abstract For lithium‐oxygen batteries (LOBs), the strong oxidant intermediate and byproducts during the charge/discharge process are the main reasons for the degradation of the electrochemical performance. Searching for highly efficient catalysts for the direct formation/decomposition of Li 2 O 2 is essential for the development of LOBs. In this study, core–shell nanostructured MoSe 2 @CNT with uniform MoSe 2 coating layers are purposefully synthesized through a facile hydrothermal strategy to address the negative intermediate and side‐product issues, therefore enhancing the battery performance. The continuous and multiwalled MoSe 2 layers can not only work as grain promoters that induce the initial nucleation and growth of equiaxed Li 2 O 2 grains on the cathode surface even under a high rate, but also prevent the byproducts formation from corrosive issues between carbon and electrolyte. Moreover, density functional theory (DFT) calculations reveal the intrinsic layer dependent direct formation/decomposition catalytic capability of 2D MoSe 2 and the LiO 2 avoidable reaction pathway during the discharge/charge process, theoretically revealing the direct epitaxial growth mechanisms of Li 2 O 2 . As a consequence, the MoSe 2 @CNT cathode exhibited a superior specific capacity over 32 000 mAh g −1 , excellent rate capabilities, and ultralong cycle life of 280 cycles at a high rate of 500 mA g −1 .