摘要
We describe a flexible and freestanding potassium-ion battery consisted of a bilayer-copper phosphide/copper nanowires (CuP <sub>2</sub> /Cu NWs) anode and perylene-3,4,9,10-tetracarboxylic dianhydride/carbon nanotubes (PTCDA@CNTs) cathode with superior rate capability and cyclability to simultaneously achieve fast K <sup>+</sup> -insertion/releasing and long shelf life on flexible-based electrodes. The extraordinary rate performance of anode and cathode deliver remarkable capacities of 90 mA h g <sup>−1</sup> at 12,000 mA g <sup>−1</sup> and 113 mA h g <sup>−1</sup> at 5250 mA g <sup>−1</sup> , respectively. Furthermore, coin-typed full cell exhibits superior charging capacities of 117.3 mAh g <sup>−1</sup> at 12,000 mA g <sup>−1</sup> and the good retention (80% after 842 cycles at 400 mA g <sup>−1</sup> ). The energy density in the high-power density region, especially the specific energy density under high power density (>10 <sup>4</sup> Wkg <sup>−1</sup> ) displayed the better rate-capability retention compared with that of reported literatures of full cells (based on the total mass of anode and cathode). Considering the flexibility and stability, the pouch batteries examined by a bending test maintained ultra-stable open circuit voltage after 5000 cycles with a bending radius of 1.2 cm. Expectedly, the state-of-art nano-engineering design and excellent performance demonstrate the direction and opportunities to further improve the energy density and safety under ultrahigh reaction rates of the wearable potassium-ion batteries.