Bzainia, AmirGomes, Catarina P.Dias, RolandoCosta, Mário Rui2024-02-222024-02-222023Bzainia, Amir; Gomes, Catarina P.; Dias, Rolando; Costa, Mário Rui (2023). Carbon-based hydrogels. In Sustainable Hydrogels: Synthesis, Properties and Applications. Amsterdam: Elsevier, p. 281-324. ISBN 978-0-3239-1753-7978-0-3239-1753-7http://hdl.handle.net/10198/29579This chapter intends to give insight into the use of carbon-based hydrogels for energy storage and/or conversion, which are becoming critical, given the ongoing need for decarbonization and growing renewable energy production. The ability to use sustainable materials and the added advantage to incorporate tailor-made, nontoxic, cheap, and electrochemically active functional moieties during their synthesis make them frontrunner materials in the field of green chemistry and energy applications. Here, after a brief introduction of graphene-, synthetic polymer-, and natural polymer-based hydrogels and many possibilities for their hybrid combination, a particular emphasis is given to their application to energy storage, energy conversion, and energy efficiency enhancement systems. Application examples concerning metal-air batteries, fuel cells, water electrolyzers, microbial fuel cells, photoelectrochemical water splitting, supercapacitors, lithium-ion batteries, and other metal-ion batteries, desalination, and water purification through solar vapor generation are highlighted.engBatteriesEnergy storage and conversionFuel cellsGraphene; HydrogelsNatural polymerSynthetic polymerWater electrolyzersbook part10.1016/B978-0-323-91753-7.00016-8