Lithium-Ion Thermal Charging Cell with Giant Thermopower for Low-Grade Heat Harvesting

Liquid-based thermoelectric cells integrate energy harvesting and storage technology, becoming the focus of energy fields. However, the simultaneous implement of high output voltage and heat-to-electricity efficiency is still challenging. Herein, we propose a lithium-ion thermal charging cell using lithium anode and electrospun zinc vanadate@carbon nanofiber cathode. Benefitting from the superior performance of electrode and the significant difference between the size of cation and anion in electrolyte, such system can continuously realize the harvesting and conversion of low-grade heat into electricity. Consequently, an open-circuit voltage of about 2.1 V can be generated at a low temperature gradient of 25 K together with an ultrahigh thermopower of 47.9 mVK(-1) and a remarkable power density of 9.2 Wm(-2). Moreover, an impressive Carnot-related efficiency (5.2%) can be achieved under same conditions. This work confirms the superiority of organic thermoelectric system and provides a new insight to develop promising thermal charging cell for sustainable applications.