High well‐matched energy gravimetric–volumetric symmetric super‐capacitor derived from hollow paper stack‐like biomass‐based functional carbon

Abstract

BACKGROUND: Two-and three-dimensional porous activated carbon (C)-based symmetrical supercapacitors show great potential for extraordinary gravimetric performance as sustainable energy storage. However, the applications of portable and microdimensional supercapacitors are limited by their low volumetric performance stemming from reduced density resulting from increased porosity and high fabrication costs. This study aimed to demonstrate the high gravimetric-volumetric performance of symmetrical supercapacitors from biomass-based porous carbon-sources materials through an environmentally benign development method. Unique porous C sourced from TENERA-type palm oil stick waste was prepared using potassium hydroxide (KOH) as an activating agent. The electrode set resembled a solid plate with an encapsulation density of ≈1.40 g cm −3 .RESULT: The study used superior gravimetric-volumetric electrode materials, including an adjusted specific surface area of 934 m 2 g −1 , single-doped optimization, and a hollow paper-stack-like morphological structure with a high C content of 91%. The results showed that the best electrode in the 1 mol L −1 H 2 SO 4 electrolytes exhibited a high gravimetric capacitance of 233 F g −1 and an extraordinary volumetric capacitance of 326 F cm −3 at 1 A g −1 . Furthermore, their coulombic efficiency was ≈99.1% at 10 A g −1 . The symmetrical electrode device performed a high gravimetric-volumetric energy density of 19.03 Wh kg −1 and 26.6 Wh L −1 at a maximum output power density of 1.7 kW kg −1 and 1.9 kW L −1 , respectively. CONCLUSION: These results indicate that the applied method development and the C-biomass-based electrode material design could achieve a high, well-matched gravimetric-volumetric performance balance in symmetric supercapacitor devices.

Short-Range Ordered Porous Carbon Derived from Confined-Region Activation Strategy Exhibits Excellent High-Loading Performance in Supercapacitors

“…Increasing the compaction density of the porous carbon material and the coating thickness of the electrodes are effective ways to enhance the gravimetric/volumetric energy density as well as power density in symmetric EDLCs. Nevertheless, these will also increase the electrochemical impedance of electrodes, thus limiting the transmission rate of ions and electrons . This is mainly ascribed to the fact that the porosity of porous carbon materials was greatly in contradiction with the graphitization degree and compaction density.…”