2D VOPO₄ Pseudocapacitive Ultrafast‐Charging Cathode with Multi‐Electron Chemistry for High‐Energy and High‐Power Solid‐State Lithium Metal Batteries

Abstract

Lithium metal batteries (LMBs) are acknowledged to be one major direction for next‐generation energy storage devices. However, the practical applications of LMBs are certainly limited by the low power density and safety issues owing to the lack of high‐capacity pseudocapacitive cathode materials and solid electrolytes. Herein, the rational synthesis of 2D VOPO4 nanosheets with enriched V4+ defects (VOPO4@G‐Air) enabling ultrafast multi‐electron reactions as a high‐capacity pseudocapacitive cathode is reported. Through V4+ defect engineering, the larger polarizationand inhomogeneous multi‐electron reactions are vastly improved, resulting in remarkably fast kinetics. Benefiting from the ultrathin 2D structure and controllably regulated V4+ defect concentration, a high discharge capacity of 313 mA h g−1at 0.1C is achieved, anda large capacity of 116 mA h g−1 is offered at 50C. Finally, utilizing the as‐synthesized VOPO4@G‐Air and a solid‐state electrolyte based on ethoxylated trimethylolpropane triacrylate (ETPTA‐LiClO4‐SSE) , the assembled solid‐state LMBs (Li||ETPTA‐LiClO4‐SSE||VOPO4) show high energy density of 85.4 Wh kg−1 at 114.5 W kg−1 and high power density of 2.3 kW kg−1 at 45.86 Wh kg−1. Further, the pouch cell unveils extraordinary safety and excellent flexibility. This work provides new insights in the construction of ultrafast and high‐capacity pseudocapacitive cathodes with multi‐electron reactions for solid‐state LMBs.

The improvement of the high voltage performance of LiCoO2 by coating LiTaO3via magnetron sputtering

“…1–4 With the increasing demand for lithium-ion battery performance, it is very crucial to develop batteries with higher energy density and power density, which is mainly limited by the cathode materials. 5 At present, great progress has been made in related research on transition metal oxides, such as Li-rich cathode materials 6,7 and Ni-rich cathode materials. 8–12 However, problems such as structural instability, voltage degradation, and poor thermodynamic stability of these materials have limited their commercialization.…”

Ionic liquid-mediated PEO-based solid-state electrolyte membrane modified with Dawson-type polyoxometalates

“…With the rapid development of the world economy, the human demand for non-renewable fossil fuels such as coal and oil is increasing [1,2]. To reduce carbon emissions, it is urgent to find and develop low-pollution renewable energy sources [3].…”