Ampere-hour-scale soft-package potassium-ion hybrid capacitors enabling 6-minute fast-charging.
Extreme fast charging of Ampere-hour (Ah)-scale electrochemical energy storage devices targeting charging times of less than 10 minutes are desired to increase widespread adoption. However, this metric is difficult to achieve in conventional Li-ion batteries due to their inherent reaction mechanism and safety hazards at high current densities. In this work, we report 1 Ah soft-package potassium-ion hybrid supercapacitors (PIHCs), which combine the merits of high-energy density of battery-type negative electrodes and high-power density of capacitor-type positive electrodes. The PIHC consists of a defect-rich, high specific surface area N-doped carbon nanotube-based positive electrode, MnO quantum dots inlaid spacing-expanded carbon nanotube-based negative electrode, carbonate-based non-aqueous electrolyte, and a binder- and current collector-free cell design. Through the optimization of the cell configuration, electrodes, and electrolyte, the full cells (1 Ah) exhibit a cell voltage up to 4.8 V, high full-cell level specific energy of 140 Wh kg-1 (based on the whole mass of device) with a full charge of 6 minutes. An 88% capacity retention after 200 cycles at 10 C (10 A) and a voltage retention of 99% at 25 ± 1 °C are also demonstrated.
Acknowledgements: This work was financially supported by the National Natural Science Foundation of China (Grant nos. 52274298 (H. Zhou), 51974114 (H. Zhou), 51672075 (Y. Kuang) and 21908049 (Y. Kuang)), and Faraday Institute - Battery Study and Seed Research Project (Rational design and manufacture of stacked Li-CO2 pouch cells) (FIRG052, Y. Zhao). National Supercomputing Center in CHANGSHA is acknowledged for allowing the use of computational resources including TIANHE-1.