High‐Performance Aqueous Supercapacitors Based on Biomass‐Derived Multiheteroatom Self‐Doped Porous Carbon Membranes

Abstract

Porous carbons derived from widely accessible, renewable, and low‐cost biomass are being extensively pursued as biocompatible electrode materials for next‐generation supercapacitors (SCs), but their practical application is being largely restricted by insufficient performance related to their powdery status. Herein, a porous carbon membrane (denoted as lettuce‐derived carbon membrane [LCM]) is developed by direct and controllable carbonization of biomass lettuce. By taking the advantages of the inherent microstructure and composition of the lettuce, the as‐fabricated LCM electrode is endowed with a large specific surface area, interconnected hierarchical pores, and multiheteroatom (N, P, and S) doping. The benefits originating from the structure synergy provide this LCM electrode excellent electrochemical performance in an aqueous symmetric SC, exhibiting a high specific capacitance of 213.4 F g−1 at 0.2 A g−1, outstanding rate capability (78.6% capacitance retention at 10 A g−1), and superior cycling stability (96.9% capacitance retention after 100 000 cycles at 5 A g−1) and unit Coulombic efficiency. Notably, the LCM‐based SC delivers the highest energy density of 7.41 Wh kg−1 with a power density of 50.4 W kg−1 at 0.2 A g−1. This device‐compatible porous carbon membrane can be applied to other advanced energy‐storage and conversion devices with a high electrochemical performance.

Advances in Micro-/Mesopore Regulation Methods for Plant-Derived Carbon Materials

“… Plants rich in heteroatoms: Elm Flower [ 37 ], Datura stramonium seed pods [ 20 ], bamboo [ 38 ], Pinecone [ 39 ], Durian peel [ 40 ], Rice husk [ 41 ], Peanut meal [ 42 ], Typha orientalis leaves [ 43 ], Lettuce slice [ 44 ], Soybean pods [ 45 ], Onion skin [ 14 ], Camellia japonica flowers [ 35 ], Duckweed [ 36 ], Hollyhock leaves [ 46 ], Cottonseed meal [ 47 ], Pomelo peel [ 48 ], Cherry flowers [ 49 ]. …”

Lignocellulosic Biomass-Derived Carbon Electrodes for Flexible Supercapacitors: An Overview

“…The assembled flexible solid-state supercapacitor device had a volumetric capacitance of 326 F/cm 3 at 0.5 A/g. Cane stalk [ 204 ] or sugarcane bagasse [ 205 ], porous lettuce slice [ 206 ], corncob sponge [ 207 ], soybean pod [ 208 ], kenaf stem [ 209 ], jute [ 210 , 211 ], fruit shell [ 212 ], and cotton [ 213 ] have also been directly converted to carbon film electrodes for flexible supercapacitors, which are summarized in Table 5 . They all demonstrated good pore characteristics, which correspond to the excellent EC performance of flexible supercapacitors.…”

Transition Metal‐Cross‐Linked‐Starch Aerogel‐Derived Porous Carbon‐Based Monolithic Chainmail Electrodes for High‐Current‐Density and Durable Alkaline Water Splitting

“…Some self-supported carbon-based chainmail electrocatalysts have been developed based on various natural biomass-derived carbon matrix with inherent hierarchical porous structures, but the difficulty of further control over the compositions and microstructures of these carbon matrix restricts their application towards controllable fabrication of carbon-based chainmail electrocatalysts with desirable functionalities. [43][44][45] Herein, a porous carbon-based monolithic chainmail electrode (Co 2 P@CSA) is fabricated via the direct carbonization of Co 2 + -cross-linked-starch aerogel (Co 2 + -SA) followed by vapor phosphorization. The mechanically strong, hierarchically porous carbon membrane comprising interconnected hollow carbon spheres obtained from SA framework serves as an ideal host for nucleation and loading of active catalyst components, contributing to fast gas and electrolyte diffusion.…”

“…Thus, the rational design and fabrication of binder‐free and self‐supported chainmail electrocatalysts that possess abundant, accessible, and robust active sites, as well as favorable multiphase gas and electrolyte diffusion characteristics is still highly required. Some self‐supported carbon‐based chainmail electrocatalysts have been developed based on various natural biomass‐derived carbon matrix with inherent hierarchical porous structures, but the difficulty of further control over the compositions and microstructures of these carbon matrix restricts their application towards controllable fabrication of carbon‐based chainmail electrocatalysts with desirable functionalities [43–45] …”