Novel electrode geometry for high performance CF/Fe2O3 based planar solid state micro-electrochemical capacitors

Three-dimensional carbon foam-metal oxide-based asymmetric electrodes for high-performance solid-state micro-supercapacitors

A three-dimensional carbon foam (CF)-based asymmetric planar micro-supercapacitor is fabricated by the direct spray patterning of active materials on an array of interdigital electrodes. The solid-state asymmetric micro-supercapacitor comprises the CF network with pseudocapacitive metal oxides (manganese oxide (MnO), iron oxide (Fe₂O₃)), where CF-MnO composite as a positive electrode, and CF-Fe₂O₃ as negative electrode for superior electrochemical performance. The micro-supercapacitor, CF-MnO//CF-Fe₂O₃, attains an ultrahigh supercapacitance of 18.4 mF cm^-2 (2326.8 mF cm^-3) at a scan rate of 5 mV s^-1. A wider potential window of 1.4 V is achieved with a high energy density of 5 μW h cm^-2. The excellent cyclic stability is confirmed by 86.1% capacitance retention after 10 000 electrochemical cycles.

Celery-derived porous carbon materials for superior performance supercapacitors

Supercapacitors are of paramount importance for next-generation applications, demonstrating high energy output and an ultra-long cycle life, and utilizing green and sustainable materials. Herein, we utilize celery, a common biomass from vegetables, by a facile low-cost pyrolysis and activation method for use in high-voltage, high-energy, and high-power supercapacitors. The as-synthesized hierarchically porous carbon materials with a high surface area of 1612 m2 g-1 and a large quantity of nitrogen and phosphorus heteroatoms exhibit a high specific capacitance of 1002.80 F g-1 at 1 A g-1 and excellent cycling stability of 95.6% even after 10 000 cycles (10 A g-1) in aqueous electrolytes. Moreover, the assembled symmetric cell delivers a high energy density of 32.7 W h kg-1 at 1200 W kg-1 and an ultra-high stability (loss of 4.8% after 10 000 cycles). Therefore, the outstanding electrochemical performance of the materials will be of use in the development of high-performance, green supercapacitors for advanced energy storage systems.