Ionic Organic Thermoelectrics with Impressively High Thermopower for Sensitive Heat Harvesting Scenarios

摘要

As the worldwide energy crisis is worsened, thermoelectric materials thatcan harvest low-grade waste heat and directly convert it into electricityprovide promising alternative energy sources. Emerging ionic thermoelectrics(iTEs) have recently attracted widespread attention thanks to theirimpressively high thermopower that can reach hundreds of times more thanconventional electronic thermoelectrics (eTEs). Based on the Soret effect,the performances of iTEs depend on the thermo-diffusion of mobile ions inelectrolytes, resulting in electrical characteristics distinct from eTE materialsand opening up additional potential applications of thermoelectrics. Amongthese materials, organics-based iTEs (i-OTEs) provide unique advantagessuch as low-cost, light-weight, and eco-friendliness, thereby offeringmore promising application scenarios that can utilize dissipated heat, forexample, from human bodies or mobile devices. This concise review beginswith the comparison of iTE and eTE, and then discusses their differentmechanisms and applied devices in detail. Next, the recent advances ofi-OTEs will be in-depth highlighted, including the merits and weaknesses ofrepresentative types of materials, effects of additives, and effective strategiesfor performance optimization. Finally, the state-of-the-art achievementsof i-OTEs are summarized, and an overview is provided of the existingchallenges and an outlook of prospective development and applications infuture efforts.