Molecularly Coupled Two-Dimensional Titanium Oxide and Carbide Sheets for Wearable and High-Rate Quasi-Solid-State Rechargeable Batteries

High-performance, flexible, and lightweight powering electrodes are urgently needed to meet the increasing interest in deformable electronic devices, particularly those utilizing solid-state electrolytes and performing at high charging rates, which unfortunately have remained a formidable challenge. Here, by regularly stacking two-dimensional (2D) titanium oxide and carbide sheets, in which the two kinds of sheets are coupled at the molecular level, a self-standing electrode is achieved with ideal mechanical durability and excellent electrochemical performance, including superb rate performance (delivering a capacity of 114 mAh g(-1) in 3.4 min) and good cycling stability (remaining >93% after 1000 cycles at 1000 mA g(-1)). Profiting from these advantages, a flexible and safe full lithium-ion battery, employing a poly(ethylene glycol) diamine-based gel polymer as the electrolyte, possesses an excellent power density of 1412 W kg(-1) while maintaining a high energy density of 59 Wh kg(-1), which outperforms most documented flexible batteries that utilize liquid electrolytes and is even comparable with some cells using coin configurations. Importantly, the performance was well maintained under mechanical deformation and after multiple breaking and self-healing cycles, demonstrating the feasibility for practical application in wearable powering devices. The results highlight the numerous possibilities for utilizing sheet materials to fabricate wearable electrode materials.