Boron doped MXenes as redox catalyst for highly efficient and reversible polysulfide conversion

Abstract

Due to the accumulation of soluble polysulfides during the process reaction process, the shuttle effect emerges and significantly impacts the electrochemical performance. The development of novel efficient catalysts and adsorbents is a very popular way to fabricate the sulfur host materials. MXene as one of the most novel and popular materials have been wildly used in electrochemical energy storage. While the limited catalytic activity and adsorption capacity hindering its application in lithium sulfur batteries. Here, we introduced boron atoms as dopants in a creative modification of MXene (B-MXene). The introduced B atoms can effectively mitigate the “shuttle effect” through chemical adsorption, owing to their electron-deficient nature. Furthermore, the introduction of boron atoms and vacancy can modify the electronic structure, enhancing the catalytic activity of MXene by providing empty perpendicular-orientation orbitals. As a result, B-MXene exhibited excellent electrochemical performance, maintaining at 943 mA h g−1 at a current density of 1.0C, after 500cycles, with a corresponding decay rate as low as 0.046 %. This work proposes an efficient strategy to fabricate highly efficient electrocatalysts for advanced lithium-sulfur batteries (Li-S batteries).