In situ construction of a hierarchical TiO₂/Ti₃C₂ hybrid via water steam etching for high-performance potassium-ion batteries

Potassium ion batteries (PIBs) have attracted great research interest in new-generation large-scale energy storage considering their abundant source, low cost, and suitable working potential. Herein, a hierarchical TiO2/Ti3C2 hybrid is developed via a green, facile water steam etching method for realizing an efficient and durable anode material for PIBs. In this hierarchical assembly, the TiO2 nanoparticles anchored on the Ti3C2 surface contribute a high pseudocapacitance while mitigating the restacking of the Ti3C2 MXene skeleton, which ensures mechanical robustness to accommodate large K+ ions. Benefiting from the amalgamation of structural properties and the synergistic effects stemming from the individual constituents, the optimized TiO2/Ti3C2 anode harvests remarkable performance in the potassium ion storage, including a high reversible capacity of similar to 255 mA h g(-1) at 0.2 A g(-1) after 1300 cycles as well as an outstanding long-term cycling performance and rate capability (a high capacity of similar to 230 mA h g(-1) even after intensive 10 000 cycles at 2 A g(-1)). The excellent TiO2/Ti3C2 anode enables the assembled pouch-cell coupling PTCDA cathode to deliver a capacity of similar to 173 mA h g(-1) at 0.05 A g(-1) and retain 120 mA h g(-1) after 30 cycles. The employment of the pouch-cell in successfully powering the LED module showcases its application prospect for advanced PIBs.