The remote controllable photothermal elastomers can realize precise non-contact control through photothermal conversion effect, highlighting a new routine for light energy utilization and a promising direction for smart materials. Developing...

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Hydrogels with excellent mechanical properties and high conductivity are key materials for the development of flexible electronic devices, smart soft robots, and so forth. However, the preparation of high-performance conductive hydrogels remains a challenge. Enlightened by the strengthening mechanism of skeletal muscles, a green muscle-like conductive hydrogel was prepared through a repeated mechanical training process. Using cellulose nanofibrils (CNFs) as the fiber reinforcing source, partial depolymerized enzyme hydrolyzed lignin as the interfacial binding agent, and Ag+ as the conducting medium in a polyvinyl alcohol (PVA) matrix, the prepared composite hydrogel exhibited anisotropic high strength, high toughness, and excellent conductivity. Through the introduction of double physical enhancement networks and the adoption of a mechanical training method that mimics the muscle strengthening principle, the enhancement effect of CNFs was maximally demonstrated in the PVA composite hydrogel. Meanwhile, this study also provides a new and effective reference for the preparation of high-performance green hydrogels.

Owing to its high aromaticity and carbon content, technical lignin as the by-product of chemical pulping and bio-refining industry can be converted into lignin-derived porous carbon (LPC) materials after activation, which is a promising strategy for high-value utilization. In particular, LPC with a higher surface area and graphitization will have a broad prospect as the electrode material for lithium-ion batteries (LIBs). However, the structure of technical lignin varies greatly due to its different industrial processes and botany sources, which remarkably affects the activation process and electrochemical properties of LPC. Herein, we study the effect of oxygen/carbon (O/C) ratio and molecular weight on the structure of LPC by exploring the effect of four kinds of technical lignin on K2CO3 activation. High O/C ratio can promote LPC to maintain a high specific surface area (SSA). High molecular weight and low O/C ratio were beneficial to increase the graphitization degree and keep the porous structure of LPC. The electrochemical performance evaluation showed that high graphitization and stable porous structure were beneficial for lithium-ion storage. Therefore, LPC from enzymatic hydrolysis lignin (EHL) had long cycle performance (490 mAh · g−1 at a current density of 400 mA · g−1) and excellent rate performance compared to lignin from chemical pulping.

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