Compacted N‐Doped 3D Bicontinuous Nanoporous Graphene/Carbon Nanotubes@Ni‐Doped MnO₂ Electrode for Ultrahigh Volumetric Performance All‐Solid‐State Supercapacitors at Wide Temperature Range

Abstract

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.202203166. Developingwide temperature range flexible solid-state supercapacitors with high volumetric energy density is highly desirable to meet the demands of the rapidly developing field of miniature consumer electronic devices and promote their widespread adoption. Herein, high-quality dense N-doped 3D porous graphene/carbon nanotube (N-3DG/CNTs) hybrid films are prepared and used as the substrate for the growth of Ni-doped MnO 2 (Ni-MnO 2 ). The integrated and interconnected architecture endows N-3DG/CNTs@Ni-MnO 2 composite electrodes' high conductivity and fast ion/electron transport pathway. Subsequently, 2.4 V solid-state supercapacitors are fabricated based on compacted N-3DG/CNTs@Ni-MnO 2 positive electrodes, which exhibit an ultrahigh volumetric energy density of 78.88 mWh cm -3 based on the entire device including electrodes, solid-state electrolyte, and packing films, excellent cycling stability up to 10 000 cycles, and a wide operating temperature range from -20 to 70 °C. This work demonstrates a design of flexible solidstate supercapacitors with exceptional volumetric performance capable of operation under extreme conditions.

Mesoporous Cobalt Oxide (CoOx) Nanowires with Different Aspect Ratios for High Performance Hybrid Supercapacitors

“…The urgent need for power sources in the power grid has driven extensive research on novel energy storage devices [ 1 , 2 , 3 , 4 , 5 ]. SCs with rapid discharge and broad working temperature range are widely studied as green energy storage devices [ 6 , 7 ]. Electric double-layer capacitors utilize a process of physical adsorption and desorption, in which carbon materials (graphene, carbon nanotubes) are generally used as active materials, which are characterized by long lifetimes but low specific energy [ 8 ].…”

Solar‐Photoactivated Nanoporous Graphene Aerogel Flowers for High‐Performance Supercapacitors

“…However, the deviations from the ideal rectangular form suggest a relatively low mutual effect between electrolyte ions and electrode materials. [ 32 ] In contrast, element doping, such as oxygen and nitrogen, can facilitate the redox reactions, leading to changes in electronic states at the doping sites or adjacent carbon atoms. Therefore, the effects of weak Faraday pseudo‐capacitance generated by oxygen and nitrogen doping in the material cannot be completely ruled out.…”

Potential of MnO2‐based composite and numerous morphological for enhancing supercapacitors performance

“…Regarding it, 2.4 V solid-state supercapacitors with an ultrahigh volumetric energy density of 78.88 mW h/cm 3 are created. 172 On the other hand, it is also reported that NiO@MnO 2 /N-doped graphene oxide materials can produce a specific capacitance of 1490 F/g at .5 A/g. 173 Compared with the Fe-doped MnO 2 composite, which has an energy density of 49.7 W h/kg at the specific power density of 879.6 W/kg, 174 NiO@MnO 2 /N-doped graphene oxide still has a higher energy density of 477 W h/kg, and a power density of 1,844 W/kg.…”

“…The N‐3DG/CNTs@NiMnO 2 composite electrodes with high conductivity and fast ion/electron transfer paths. Regarding it, 2.4 V solid‐state supercapacitors with an ultrahigh volumetric energy density of 78.88 mW h/cm 3 are created 172 . On the other hand, it is also reported that NiO@MnO 2 /N‐doped graphene oxide materials can produce a specific capacitance of 1490 F/g at .5 A/g 173 .…”