High-Performance Biomass-Based Flexible Solid-State Supercapacitor Constructed of Pressure-Sensitive Lignin-Based and Cellulose Hydrogels

Abstract

Employing renewable, earth-abundant, environmentally friendly, low-cost natural materials to design flexible supercapacitors (FSCs) as energy storage devices in wearable/portable electronics represents the global perspective to build sustainable and green society. Chemically stable and flexible cellulose and electroactive lignin have been employed to construct a biomass-based FSC for the first time. The FSC was assembled using lignosulfonate/single-walled carbon nanotube (Lig/SWCNT) pressure-sensitive hydrogels as electrodes and cellulose hydrogels as an electrolyte separator. The assembled biomass-based FSC shows high specific capacitance (292 F g at a current density of 0.5 A g), excellent rate capability, and an outstanding energy density of 17.1 W h kg at a power density of 324 W kg. Remarkably, the FSC presents outstanding electrochemical stability even suffering 1000 bending cycles. Such excellent flexibility, stability, and electrochemical performance enable the designed biomass-based FSCs as prominent candidates in applications of wearable electronic devices.

“Waste to Wealth”: Lignin as a Renewable Building Block for Energy Harvesting/Storage and Environmental Remediation

“…In addition to the EDLCs, lignin‐derived carbon electrodes can be used for pseudocapacitors. To increase the pseudocapacitive and electrochemical properties of lignin‐based electrodes, researchers improved them by using two distinct methods: (1) loading electroactive species, such as transition‐metal oxides (e.g., NiO, FeO, MnO 2 , NiCo 2 O 4 ) or heteroatoms (e.g., N, Cu) into lignin‐derived carbon; and (2) self‐assembly of lignin with conducting materials (e.g., polyaniline, PPy, PEDOT, graphene, carbon nanotubes (CNTs)). Zhang et al.…”

Lignin-Based Hydrogels: Synthesis and Applications

“…An assembly of lignosulfonate/single-walled carbon nanotube hydrogels was used as electrodes for the formation of FSC by using cellulose hydrogels as electrolyte separators. The reported FSC present high specific capacitance, 292 F/g at the current density of 0.5 A/g, and excellent energy density of 17.1 W•h/kg [95].…”

Lignin‐derived electrochemical energy materials and systems

“…As reported before, a well designed composite of reduced graphene oxides (rGOs) and confined lignin nanocrystals with favorable interplay exhibited highly reversible pseudo capacitive behavior from the enhanced redox reactivity of quinone structures confined on the surface . Electroactive lignin was also used to assemble lignosulfonate / single‐walled carbon nanotube treated by HNO 3 pressure‐sensitive hydrogels for ECs applications . Lignosulfonate functionalized graphene composites were used to fabricate metal‐free and flexible supercapacitors with comparable performance like the transition meta‐based ECs …”