Modified carboxylate cellulose nanofibers/graphene composite as triboelectric and conducting electrode in single electrode triboelectric nanogenerator with superior acid/alkali resistance.

Single-electrode triboelectric nanogenerator (SE-TENG) is essentially useful when only one triboelectric electrode can connect to external load. Conventional metal electrodes are susceptible to corrosion in open environments characterized by high humidity and acidic or alkaline conditions. Thus, the material used for the triboelectric layer must exhibit robust resistance to environmental acids and alkalis. To achieve this target, advancements have been made to wrap up metal electrodes or substitute it with non-metallic conductive materials. However, the non-metallic conductive materials have not been explored their capabilities of acting as both electrodes and triboelectric layers. In this work, carboxylate cellulose nanofibers (CNF), graphene nanosheets (GN), and citric acid (CA) were utilized to create a conductive nanofiber/graphene (CNF/GN-CA) film with superior acid/alkali resistance. We develop a single-electrode mode TENG named CGC-TENG, in which this CNF/GN-CA worked as both an electrode and a triboelectric material. The CGC-TENG demonstrated stable output over 15,300 cycles and remained stable after 10 h immersion in pH = 1 and pH = 14 solutions, showing superior acid/alkali resistance. Based on the better performance of CNF/GN-CA film with long-term stability, CGC-TENG was demonstrated as a "trigger functional sensor" with rapid response speed (0.35 s) and short recovery time (0.25 s). Thus, the CGC-TENG holds significant promise for applications in human-computer interaction systems under various harsh environmental conditions.