Inspired by Wood: Thick Electrodes for Supercapacitors

Abstract

The emergence and development of thick electrodes provide an efficient way for the high-energy-density supercapacitor design. Wood is a kind of biomass material with porous hierarchical structure, which has the characteristics of a straight channel, uniform pore structure, good mechanical strength, and easy processing. The wood-inspired low-tortuosity and vertically aligned channel architecture are highly suitable for the construction of thick electrochemical supcapacitor electrodes with high energy densities. This review summarizes the design concepts and processing parameters of thick electrode supercapacitors inspired by natural woods, including wood-based pore structural design regulation, electric double layer capacitances (EDLCs)/pseudocapacitance construction, and electrical conductivity optimization. In addition, the optimization strategies for preparing thick electrodes with wood-like structures (e.g., 3D printing, freeze-drying, and aligned-low tortuosity channels) are also discussed in detail. Further, this review presents current challenges and future trends in the design of thick electrodes for supercapacitors with wood-inspired pore structures. As a guideline, the brilliant blueprint optimization will promote sustainable development of wood-inspired structure design for thick electrodes and broaden the application scopes.

Perspectives of Wood-Inspired Electro-Fenton Catalysis for Energy-Efficient Wastewater Decontamination

“…31 Unlike the electrodes where powder catalysts are bound to a current collector using organic binders and conductive additives, wood-derived carbon electrodes, as freestanding electrodes, effectively circumvent the reduction in mass loading of active materials and reduce manufacturing costs. 40 Furthermore, loading materials onto the wood surface will result in unique morphologies and distinct performances. These approaches, including pore engineering, 37,110 organic heteroatom doping, 111,112 metal/metal oxide particle loading, 19,113,114 and single-atom-catalyst loading, 39,115 are conducive to wood functionalization in electrochemical applications.…”

“…Heteroatoms such as oxygen (O), nitrogen (N), and sulfur (S) with higher electronegativities than carbon (C), as well as phosphorus (P) or boron (B) with lower electronegativities, can be introduced into the carbon framework, introducing polarized active sites regulated by chemical dopants and functionalities. In woodderived carbons, dopants or organic modifiers can alter the electronic distributions, surface chemistry, and charge transportation, 40 leading to regulated electrochemical performances. In the wood-derived carbon with heteroatom doping, the carbonized wood acts as active sites.…”

“…In general, direct carbonization has been employed to produce wood-derived thick electrodes, which exhibit excellent performance in ion, water, gas, and electron transfer . Unlike the electrodes where powder catalysts are bound to a current collector using organic binders and conductive additives, wood-derived carbon electrodes, as freestanding electrodes, effectively circumvent the reduction in mass loading of active materials and reduce manufacturing costs . Furthermore, loading materials onto the wood surface will result in unique morphologies and distinct performances.…”

Sponge-Inspired Super-Lightweight Porous Carbon Nanohybrid Fiber Aerogels: Implications for High-Performance Electrodes

“…Increasing the electrode thickness to enhance the loading of active materials per unit area or designing scaffold structures capable of accommodating high-quality electrode materials are crucial approaches to achieve this goal. , However, the electrochemical performance of thick electrodes is significantly influenced by the pore structure and electrolyte infiltration. Increasing the thickness lengthens the ion and electron transport pathways, leading to unfavorable effects on the electrochemical energy storage behavior. , Hence, it is necessary to design thick electrodes with appropriate pore structures and investigate the influence of thickness on the performance of supercapacitors. , The combination of electrospun three-dimensional fiber sponge structures addresses both aspects and can solve the above-mentioned problems. The larger internal pore structure of three-dimensional carbon nanofiber sponges provides space favorable for electrolyte infiltration, facilitating rapid ion transport. , However, an excessively high thickness also affects the electrochemical performance of the electrode .…”

Hollow N-doped carbon nano-mushroom encapsulated hybrid Ni3S2/Fe5Ni4S8 particle anchored to the inner wall of porous wood carbon for efficient oxygen evolution electrocatalysis

“…As one of the most abundant natural resources on the earth, wood possesses a hierarchically porous structure containing numerous multiscale-oriented channels for moisture and nutrient transport. 32 Hollow wood cells are well-arranged along the longitudinal direction of wood and structurally interconnected through pits traversing the cell walls to constitute a 3D transport network in wood. 33 Additionally, exposed rich functional groups favor the chemical modification of active substances on wood.…”