Woods can be depolymerized into small molecules through hydrolysis, pyrolysis, oxidation, reduction, and biodegradation to produce biofuels and fine chemicals.

Lignin is the most abundant potential renewable resource of aromatic structural units. Turning lignin into high-value compounds, such as fuels, adhesives or refined chemicals, is the cornerstone and focus of biorefinery in the future. Depolymerization of lignin can convert its macromolecules towards smaller molecules (monomers or oligomers) allowing it to be used for further applications. Electrochemical depolymerization is an excellent method of green and sustainable transformation, which can effectively avoid reagent waste and mild reaction. This review pretents the research progress of lignin electrochemical oxidation in recent years, summarizes the effects of solvent system (alkaline solvent, ionic liquid and deep eutectic solvents, as well as different lignin concentration and medium), electrode materials (platinum, gold, copper, nickel, cobalt, lead dioxide, tin dioxide and titaniumbased metal electrodes) and electrolytic parameters (current density, temperature, reaction time and photocatalysis) on the oxidative degradation efficiency and product distribution of lignin, and prospects its development. The development of low-cost electrode materials and efficient solvent systems will still be an important direction for the high-value and high-quality application of lignin.

The lignosulfonate/polyaniline nanocomposite electrode material was made by polymerization of aniline with lignosulfonate as dispersant and structure-directing agent. Redox can convert the catechol/quinone groups on lignin, promoted by electron transfer of polyaniline.

Lignin carbon aerogel has high specific surface area, high porosity, excellent bioactivity and degradability of the material, it has a wide range of applications and can be used in supercapacitors, adsorbents and catalysts, etc.

Lignin, one of the components of natural plant biomass, is a rich source of carbon and has excellent potential as a valuable, sustainable source of carbon material. Low-cost lignosulfonate (LS) doped with polyaniline (PANI) has been used as a precursor to produce porous carbon. LS has a highly dispersed and sparse microstructure and can be accidentally doped with S atoms. N and S double-doped carbon can be directly synthesized with abundant mesopores and high surface area in a lamellar network using PANI as another doping source. This study explored the optimal conditions of LS/PANI material with different amounts of lignosulfonate and different carbonization temperatures. When the amount of lignosulfonate was 4 g and the carbonization temperature was 700 °C, graded porous carbon was obtained, and the electrochemical performance was the best. At 0.5 A/g, the specific capacitance reached 333.50 F/g (three-electrode system) and 242.20 F/g (two-electrode system). After 5000 charge/discharge cycles at 5 A/g, the material maintained good cycling stability and achieved a capacitance retention rate of 95.14% (three-electrode system) and 97.04% (two-electrode system). The energy and power densities of the SNC700 samples were 8.33 Wh/kg and 62.5 W/kg at 0.25 A/g, respectively, values that meet the requirements of today’s commercially available supercapacitor electrode materials, further demonstrating their good practicality. This paper provides an efficient double-doping method to prepare layered structures. Porous carbon is used for electrochemical energy storage devices.