Angew：化学预钾化以提高双碳钾离子混合电容器性能

在此，为钾离子混合电容器（PIHC）开发了一种化学预钾化策略，该策略通过在钾-萘-四氢呋喃溶液中同时处理葡萄糖衍生碳（GDC）阳极和商用活性碳（CAC）阴极。结合原位和非原位表征，证实了预钾化试剂与碳电极之间的自由基反应，这不仅使电化学不可逆位点失活，而且促进在电极上预形成均匀且致密的富KF电解质膜。因此，预钾化处理具有多重优势：（I） GDC阳极的初始库仑效率（CE）从45.4 % 提高至84.0 % 具有较高的速率能力；（II） CAC阴极表现出改进的循环CE和稳定性，这是由于在4.2 V下更好阻止了电解质氧化(III) 组装后的PIHC具有172.5 Wh kg 1的高能量密度，循环寿命超过10000次。

图1 a) Schematic illustration of the pre-potassiation process and its effects on dual-carbon potassium ion hybrid capacitor. b) The CV curve of K-Nap-THF solution with copper foil as the working electrode at 1.0 mV s 1. c) The first CV curves of the GDC-CP and GDC anodes at 0.1 mV s 1. d) The first charge/discharge curves of the GDC-CP and GDC anodes at 0.2 A g 1. e) The cycling performance of the GDC-CP and GDC anodes at 0.2 A g 1. The charge/discharge curves of the f) CAC-CP and g) CAC cathodes at 1.0 A g 1. h) The cycling performance of the CAC-CP and CAC cathodes at 1.0 A g 1.

图2 a) The 39K solid-state NMR spectra of the GDC-CP and CAC-CP powders. The XANES spectra of the b) GDC, GDC-CP and GDC-EP electrodes and the c) CAC, CAC-CP and CAC-EP electrodes at C K-edge. The evolution of elements (C, O, F, P, K) with sputtering depth for d) the GDC-CP electrode and f) the CAC-CP electrode (inset images are the TEM images of the cycled GDC-CP and CAC-CP samples, respectively.). e) The high resolution F 1s spectra along the sputtering depth of the GDC-CP and CAC-CP electrodes. The AFM images of Young's modulus distribution for the g) GDC, h) GDC-CP, i) CAC and j) CAC-CP electrodes.

图3 The SEM images of the a) CAC and b) CAC-CP cathodes at different charge/discharge voltages. The SEM images and the corresponding elemental (F, P, K) mapping images of the c) CAC and d) CAC-CP electrodes at 4.2 V, respectively. e) 3D visualization of the architectural evolutions of K2F+, PF6 , PO2 and C2H3O2 for the cycled CAC (top) and CAC-CP (bottom) electrodes, respectively. f) The molecular orbital diagrams of HOMO and LUMO for EC, PC and KPF6 with different chemical environment.

图4 a) The long-term cycling performance of the GDC//CAC and GDC-CP//CAC-CP hybrid capacitors at 1.0 A g 1 (inset images are the charge/discharge curves of the GDC//CAC and GDC-CP//CAC-CP hybrid capacitors, respectively). b) The rate performance of the GDC-CP//CAC-CP hybrid capacitor at different current densities. c) In situ monitoring of the GDC-CP//CAC-CP hybrid capacitor during charge/discharge process with a three-electrode device at 1.0 A g 1. d) Ragone plot comparisons of the GDC-CP//CAC-CP hybrid capacitor with previous reports. e) The long-term cycling performance of the GDC-CP//CAC-CP pouch cell at 1.0 A g 1 (inset digital images are the scenes of the GDC-CP//CAC-CP pouch cell driving an electric fan at different times). Note that the mass ratio of active materials of anode to cathode is 1 : 2, and the electrochemical performance of hybrid capacitor is calculated based on the total active mass of anode and cathode.

来源：Yong Qian, Bei Wu, Yang Li, Zhen Pan, Dr. Shuai Feng, Dr. Ning Lin, Prof. Yitai Qian，Integrating Chemical Pre-Potassiation with Pre-Modulated KF-Rich Electrolyte Interfaces for Dual-Carbon Potassium Ion Hybrid Capacitor，Angew. Chem. Int. Ed. 2023, 62, e202217514，https://doi.org/10.1002/anie.202217514