Authors: Xiaojun Wang, Jiaqing Qiao, Linwei Guo, Min Feng, Peng Wang, Zhiming Liu
Published: 2025-03-12
Source: Full article
AbstractLithium‐ion capacitors (LICs) are considered promising advanced energy storage devices due to their combination of high energy and power density. However, the inherent mismatch in charge storage rate between anode and cathode has forced search for anode materials with accelerated reaction kinetics. Herein, heterogeneous flower‐like SnS2@few‐layer Ti3C2 (SnS2@f‐Ti3C2) composites with asymmetric charge distribution through Sn─O─Ti bonded are prepared, which can regulate the electronic structure of active sites. Moreover, the presence of f‐Ti3C2 substrate suppresses the volume expansion of SnS2, while the SnS2 alleviates the interlayer stacking and increases the active sites of f‐Ti3C2 during charging/discharging processes. Consequently, LICs consisting of SnS2@f‐Ti3C2 anode and activated carbon (AC) cathode display high power density (6.67 kW kg−1), high energy density (126.26 Wh kg−1), and superior stability. Furthermore, the density functional theory (DFT) calculations and experimental characterizations reveal that the built‐in electric field, induced by modulating the work function of SnS2 and f‐Ti3C2 MXene, enables the directional electron transfer between heterogeneous interfaces, thereby lowering the diffusion energy barrier of Li ions and boosting the electrochemical reaction kinetics of SnS2@f‐Ti3C2 composites. This work provides guidance for designing composites with unique surface‐interface structures and modulating directional carrier transport between heterojunctions.