Direct Microstructure Tailoring of Hard Carbon Electrodes for Fabrication of Dual-Carbon Potassium-Ion Hybrid Supercapacitors
The microstructure of hard carbon, including interlayer spacing, the degree of graphitization, and doped heteroatoms, has a significant impact on the K+ storage capability of hard carbon anodes in potassium-ion hybrid supercapacitors (PIHCs). However, previously reported microstructural engineering...
Saved in:
Published in | Energy & fuels Vol. 38; no. 9; pp. 8285 - 8295 |
---|---|
Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
American Chemical Society
02.05.2024
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | The microstructure of hard carbon, including interlayer spacing, the degree of graphitization, and doped heteroatoms, has a significant impact on the K+ storage capability of hard carbon anodes in potassium-ion hybrid supercapacitors (PIHCs). However, previously reported microstructural engineering methods typically involve complex, time-consuming, and expensive multistep processes. Herein, we report the simple pyrolysis-guided microstructural engineering of hard carbon materials using cost-effective coffee waste (CW) as a recycled single carbon source for the fabrication of PIHC devices. For battery-type anodes, the direct pyrolysis of CW at various temperatures (700, 900, and 1100 °C) is conducted to control the microstructures and K+ storage behavior of hard carbon anode materials. Carbon prepared at 700 °C exhibits high specific capacity, large capacitive K+ storage contribution, and rapid K+ storage kinetics as a result of abundant surface defects and functional groups as well as a wide interlayer spacing. For capacitor-type cathodes, high surface area activated carbon is prepared using an industrially available KOH activation method. The optimized PIHC full cell exhibits a high energy density of 120 Wh kg–1, a power density of 3378 W kg–1, and a capacity retention of 83.6% after 3000 cycles at 0.5 A g–1, comparable to carbon materials synthesized by complex multistep processes. These findings indicate that simple microstructural engineering via pyrolysis is sufficient for fabricating dual-carbon PIHCs with an adequate electrochemical performance. |
---|---|
ISSN: | 0887-0624 1520-5029 |
DOI: | 10.1021/acs.energyfuels.3c04617 |