Renewable plant-derived lignin for electrochemical energy systems

Lignin-based materials have recently made substantial progress for use as electrochemical energy systems. Opportunities and challenges of lignin-based materials for future electrochemical energy systems are fully highlighted. Significant scientific discussions of structural design of lignin-based materials for electrochemical energy systems are comprehensively exhibited. Viable strategies for the construction of new sustainable energy materials are discussed in detail. Lignin, as one of the most abundant natural polymers, has been proved to be a promising material for the construction of high-performance electrochemical energy systems, including electrodes, electrolytes, and separators, because of their low-cost and sustainable natures and unique structure with abundant functional group. In this review article, we outline some key contributions in this field such as fundamental principles and various electrochemical energy systems including rechargeable batteries, supercapacitors, solar cells, and fuel cells. At the same time, we also point out the significant scientific discussion and critical barriers for lignin-based materials for electrochemical energy systems and also provides feasible strategies for preparing new sustainable energy materials. Lignin, as one of the most abundant natural polymers, has been proved to be a promising material for the construction of high-performance electrochemical energy systems, including electrodes, electrolytes, and separators, because of their low-cost and sustainable natures and unique structure with abundant functional group. In this review article, we outline some key contributions in this field such as fundamental principles and various electrochemical energy systems including rechargeable batteries, supercapacitors, solar cells, and fuel cells. At the same time, we also point out the significant scientific discussion and critical barriers for lignin-based materials for electrochemical energy systems and also provides feasible strategies for preparing new sustainable energy materials. lignin is prepared through alkaline pulping strategy. a tool for electrochemical test. a tool for thermal analysis, especially for measure of Tg. a fuel cell directly using methanol as anode active material. a fuel cell directly using solid carbon to convert chemical energy into electrical energy. a solar cell by imitating the principle of photosynthesis. When a particle carrying surface charge is immersed in an electrolyte solution, an ionic cloud appears in the immediate vicinity of the particle to neutralize its charge, this structure is called electrical double layer. lignin comes from the production of biofuel by enzymatic hydrolysis strategy. polymer electrolytes in the state of gel. transition temperature from glass state to high elastic state. lignin released from the cellulose and hemicellulose fractions during the Kraft pulping process. the structural component of plant biomass; the second most abundant biopolymer on earth after cellulose. a carbon membrane prepared by lignin-derived materials. lignin with -SO3H groups is prepared by Kraft pulping process in an acidic condition. rechargeable batteries working through moving lithium ions between the positive electrode and the negative electrode. a fuel cell directly using microorganisms to convert chemical energy into electrical energy. lignin is extracted from biomass materials via organic solvents. solar cells using organic polymers as photoelectric conversion materials. a typical inorganic nanocluster, which is composed of transition metals or rare earth elements and oxygen ligands through bridged oxygen bonds. a dye-sensitized solar cell using quasi-solid-state electrolytes instead of liquid electrolytes. high-performance batteries that uses flowable electroactive redox electrolytes for providing continuous electrochemical energy. a tool for thermal analysis. rechargeable batteries working through moving zinc ions between the positive electrode and the negative electrode.