Laser-induced graphene: Carbon precursors, fabrication mechanisms, material characteristics, and applications in energy storage

Laser-induced graphene (LIG) has emerged as a highly promising electrode material for energy storage due to its exceptional physicochemical properties, including a well-developed 3D porosity structure, high specific surface area (SSA), excellent electrical conductivity (EC), impressive mechanical strength, and outstanding electrochemical stability. These merits are attributed to the localized transient high-temperature radiation and thermal expansion effects observed during laser processing. Extensive research efforts have been devoted to expanding carbon sources, investigating the formation mechanism of LIG, achieving controllable preparation of LIG and its composites with high SSA/EC, and exploring their applications in energy storage and other domains. This review provides a comprehensive account of LIG, starting with an overview of the mainstream carbon precursors: polymer substrates, phenolic resins, and lignocellulosic materials. Subsequently, the fabrication mechanisms for transforming these carbon source matrices into 3D porous graphene are thoroughly examined. Additionally, the unique advantages of LIG and its composites are summarized, encompassing controllable surface micromorphology, high SSA and EC, efficient wetting properties with full contact angle coverage, and superior mechanical flexibility. Furthermore, the review presents an extensive survey of the applications of LIG and its doped, modified, or multi-composite materials in planar flexible supercapacitors, various battery systems (such as lithium-ion, sodium-ion, lithium-metal, metal-air, and lithium-sulfur batteries), as well as fuel cells (including bio-, chemical, microfluidic, alumina-air, and proton exchange membrane fuel cells). Finally, the review concludes with an outlook on future challenges and perspectives in the research and development of LIG materials and their associated devices in the field of energy storage.