Simultaneously Enhanced Energy Harvesting and Storage Performance Achieved by 3D Mix‐Phase Mose2‐Nise/NF.

As an energy harvesting device, the newly emerged thermocell has attracted great interest. However, it requires an additional energy storage device to complete a functional recycling system. As the core part of energy harvesting and storage devices, the design of electrodes with both high thermoelectric and electrochemical conversion efficiencies is particularly important. Herein, a high‐performance thermocell and supercapacitor device are constructed by employing the same mix‐phase MoSe2‐NiSe/NF electrode for both energy harvesting and storage. The thermocell exhibits an enhanced Seebeck coefficient of −1.69 mV K−1 and a superior output of 0.58 mW m−2 K−2 for low‐grade heat harvesting. Meanwhile, the supercapacitor device shows a great energy density of 54 Wh kg−1 at a power density of 806 W kg−1 and excellent cycling stability with a 92.8% retention rate after 50 000 cycles. This work offers a universal approach for the rational design of synergistic electrode materials to simultaneously achieve high‐energy harvesting and storage devices and lays a foundation for the recycling system of thermoelectric harvesting, conversion, and storage. [ABSTRACT FROM AUTHOR]