Built-In Electric Field-Driven Ultrahigh-Rate K-Ion Storage via Heterostructure Engineering of Dual Tellurides Integrated with Ti3C2Tx MXene
Long Pan, Rongxiang Hu, Yuan Zhang, Dawei Sha, Xin Cao, Zhuoran Li, Yonggui Zhao, Jiangxiang Ding, Yaping Wang, ZhengMing Sun
Abstract
Abstract Exploiting high-rate anode materials with fast K + diffusion is intriguing for the development of advanced potassium-ion batteries (KIBs) but remains unrealized. Here, heterostructure engineering is proposed to construct the dual transition metal tellurides (CoTe 2 /ZnTe), which are anchored onto two-dimensional (2D) Ti 3 C 2 T x MXene nanosheets. Various theoretical modeling and experimental findings reveal that heterostructure engineering can regulate the electronic structures of CoTe 2 /ZnTe interfaces, improving K + diffusion and adsorption. In addition, the different work functions between CoTe 2 /ZnTe induce a robust built-in electric field at the CoTe 2 /ZnTe interface, providing a strong driving force to facilitate charge transport. Moreover, the conductive and elastic Ti 3 C 2 T x can effectively promote electrode conductivity and alleviate the volume change of CoTe 2 /ZnTe heterostructures upon cycling. Owing to these merits, the resulting CoTe 2 /ZnTe/Ti 3 C 2 T x (CZT) exhibit excellent rate capability (137.0 mAh g −1 at 10 A g −1 ) and cycling stability (175.3 mAh g −1 after 4000 cycles at 3.0 A g −1 , with a high capacity retention of 89.4%). More impressively, the CZT-based full cells demonstrate high energy density (220.2 Wh kg −1) and power density (837.2 W kg −1 ). This work provides a general and effective strategy by integrating heterostructure engineering and 2D material nanocompositing for designing advanced high-rate anode materials for next-generation KIBs."Image missing"