Lignin-derived electrochemical energy materials and systems

Electrode and electrolyte materials with higher performance, longer life, and lower cost need to be developed, given the substantial growing demand for advanced electrochemical energy systems. Lignin, the second most abundant natural polymer, has been successfully demonstrated to be a viable precursor or feedstock for the preparation of high-performance electrochemical energy materials and components such as electrodes, electrolyte additives, membrane separators, and binders. Moreover, techno-economic analyses indicate that it is possible to prepare cost-effective carbon structures from lignin at engineering scale, in contrast with current carbon products. These facts suggest that the scalable conversion of lignin into high-value energy materials will offer a promising pathway to not only promote the utilization and valorization of lignin but also boost the development of advanced electrochemical energy systems. This review examines cutting-edge renewable energy materials derived from various lignin compounds and their applications in electrochemical energy systems with an emphasis on supercapacitors, rechargeable batteries, and fuel cells. Meanwhile, this review also aims to carve out the critical barriers for lignin-derived high-performance materials for energy applications, and to identify viable approaches for the synthesis of sustainable new energy materials.