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The proliferation of electrochemical energy storage (EES) devices demands more advanced power/energy storage technologies. Flexible quasi-solid-state supercapacitors (FSSCs) have been attracting rapid and considerable attention as they exhibit unique and promising advantages, such as a long cycle life, light weight, high power density, and environment friendliness. Hydrogels, commonly synthesized by chemical and/or physical cross-linking of monomers and/or polymers, have already become an emerging platform for the rapid development of FSSCs. Lignocellulose materials are green/sustainable, abundant, and low-cost; due to the synergy of lignocellulose and hydrogels, the development of lignocellulose-based hydrogels/aerogels with distinguished physicochemical properties (e.g., high flexibility, good mechanical strength, and rapid charge transport) offers emerging opportunities for FSSCs. This review highlights the fundamental understanding and recent developments of lignocellulose and supercapacitors, with focus on the latest concepts/technologies in developing hydro- and aerogels based on lignocellulose as major components in FSSCs, structural design, and improvement of the performance of lignocellulose-based electrodes and electrolytes. Furthermore, the challenges and opportunities during the development of lignocellulose-based hydrogels/aerogels in FSSCs are discussed. [ABSTRACT FROM AUTHOR]

An efficient separation technology for hydrolysates towards a full valorization of bamboo is still a tough challenge, especially regarding the lignin and lignin-carbohydrate complexes (LCCs). The present study aimed to develop a facile approach using organic solvent extraction for efficiently fractionating the main components of bamboo hydrolysates. The high-purity lignin with only a trace of carbohydrates was first obtained by precipitation of the bamboo hydrolysate. The water-soluble lignin (WSL) fraction was extracted in organic solvent through a three-stage organic solvent extraction process, and the hemicellulosic sugars with increased purity were also collected. Furthermore, a thorough characterization including various NMR techniques (31P, 13C, and 2D-HSQC), GPC, and GC-MS was conducted to the obtained lignin-rich-fractions. It was found that the WSL fraction contained abundant functional groups and tremendous amount of LCC structures. As compared to native LCC of bamboo, the WSL fraction exhibited more typical LCC linkages, i.e. phenyl glycoside linkage, which is the main type of chemical linkage between lignin and carbohydrate in both LCC samples. The results demonstrate that organic phase extraction is a highly efficient protocol for the fractionation of hydrolysate and the isolation of LCC-rich streams possessing great potential applications. [ABSTRACT FROM AUTHOR]

Combining chemi-mechanical pulping with autohydrolysis pretreatment is an efficient and value-added utilization approach for lignocellulosic biomass in paper industry. To further promote the utilization of autohydrolyzed biomass in chemi-mechanical pulping, the color evolution of poplar wood chips in autohydrolysis pretreatment and its chromogenic mechanism were investigated by using CIELab color system, FT-IR, NMR and GPC. The results showed that the total color difference ΔE* increased obviously, which were remarkable as the combined hydrolysis factor (CHF) increased. The lignin content led to a more significant influence on the color of poplar wood chips than the extractives. The autohydrolysis pretreatment with a higher CHF accelerated the degradation and subsequent condensation of lignin, resulting in the formation of chromophoric groups, such as Hibbert ketone, quinones and quinone methides. It is of great significance for biomass refinery and paper industry to reveal the color evolution of poplar wood chips caused by autohydrolysis pretreatment from the point of view of chemical components' structure. Unlabelled Image • The color evolution of autohydrolyzed wood chips was investigated. • Chromogenic mechanism of the wood chips in autohydrolysis process was revealed. • The color of poplar wood chips became deep after autohydrolysis with a higher CHF. • Lignin has a greater impact on the coloring of poplar wood chips than extractives. [ABSTRACT FROM AUTHOR]