Authors: Yufeng An, Zhiwei Li, Yao Sun, Zhijie Chen, Jiangmin Jiang, Hui Dou, Xiaogang Zhang
Published: 2021-11-03
DOI: 10.1002/eem2.12305
Source: Full article
Thermal energy is abundantly available in our daily life and industrial production, and especially, low‐grade heat is often regarded as a byproduct. Collecting and utilizing this ignored energy by low‐cost and simple technologies may become a smart countermeasure to relieve the energy crisis. Here, a unique device has been demonstrated to achieve high value‐added conversion of low‐grade heat by introducing redox‐active organic alizarin (AZ) onto N‐doped hollow carbon nanofibers (N–HCNF) surface. As‐prepared N–HCNF/AZ can deliver a high specific capacitance of 514.3 F g−1 (at 1 A g−1) and an outstanding rate capability of 60.3% even at 50 A g−1. Meanwhile, the assembled symmetric proton capacitor can deliver a high energy density of 28.0 Wh kg−1 at 350.0 W kg−1 and a maximum power density of 35.0 kW kg−1 at 17.0 Wh kg−1. Significantly, the thermally chargeable proton capacitors can attain a surprisingly high Seebeck coefficient of 15.3 mV K–1 and a power factor of 6.02 µW g–1. Taking advantage of such high performance, a satisfying open‐circuit voltage of 481.0 mV with a temperature difference of 54 K is achieved. This research provides new insights into construction of high value‐added energy systems requiring high electrochemical performances.