Pushing Theoretical Potassium Storage Limits of MXenes through Introducing New Carbon Active Sites

• DOI: 10.1002/adma.202408723
• Publication Date: 2024-09-11T09:07:25Z
• Authors: Xin Cao; Yuchun Liu; Huan Xia; Yuhuan Li; Li Yang; Hang Wang; Hongjun Zhang; Bangjiao Ye; Wei He; Tianchen Wei; Zhaorui Xin; Chengjie Lu; Min Zhou; ZhengMing Sun
• Keywords: MXenes; Carbon fibers

Abstract Surface‐driven capacitive storage enhances rate performance and cyclability, thereby improving the efficacy of high‐power electrode materials fast‐charging batteries. Conventional defect engineering, widely‐employed optimization strategy, primarily focuses on influence defects themselves behaviors. However, role local environment surrounding defects, which significantly affects surface properties, remains largely unexplored for lack suitable material platform has long been neglected. As proof‐of‐concept, typical Ti 3 C 2 T x MXenes are chosen as model owing to metallic conductivity tunable satisfying requirements capacitive‐type electrodes. Using density functional theory (DFT) calculations, potential with modulated atomic is anticipated introducing new carbon sites found near pores can activate electrochemically inert surface, attaining record theoretical potassium capacities (291 mAh g −1 ). This supposition realized through tailoring via chemical scissor within sublayers, exposing sp ‐hybridized active sites. The resulting demonstrate unprecedented cycling stability. Notably, higher exposure exhibit a record‐breaking capacity over 200 sustain retention than 80% after 20 months. These findings underscore effectiveness regulating defects' neighboring illuminate future high‐performance design.