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In this study, a facile pyrolysis process is utilized to convert a mantis shrimp shell into a 3D bicontinuous porous, highly wrinkled, nitrogen-doped, graphene-like ultrathin carbon sheet (3D BWGC). The 3D BWGC achieves a high surface area of 2300 m2 g−1 and a pore volume of up to 1.63 cm3 g−1. The specific capacitance of the 3D BWGC in 0.5 M H2SO4 electrolyte is 370.9 F g−1 at a current density of 1 A g−1 and an operating voltage window of 1.1 V. By introducing Fe2+, the operating voltage window of 3D BWGC symmetric supercapacitors can reach 1.8 V in a neutral electrolyte, and a specific capacitance of 317.2 F g−1 can be obtained at a current density of 0.5 A g−1. Remarkably, the fabricated symmetric supercapacitors using 2 M MgSO4 + 0.05 M FeSO4 electrolyte demonstrated an energy density as high as 17.7 W h kg−1 at a power density of 180 W kg−1. The assembled supercapacitors exhibit good cycling performance, maintaining an initial capacitance of 87.2% over 30 000 cycles. These excellent performances indicate the promising prospects of 3D BWGC in high-performance electrochemical energy storage. [ABSTRACT FROM AUTHOR]

Capacitive lithium-ion batteries with a dual-energy storage mechanism can provide a high energy and power density, which are constructed by the addition of slightly porous carbon. Here, the effect from porous carbon, such as the proportion, specific surface area, pore size and electrical conductivity, on the rate performance is systematically studied using hybrid electrodes with LiNi 0.6 Co 0.2 Mn 0.2 O 2 and activated carbon or carbon aerogel. Compared with LiNi 0.6 Co 0.2 Mn 0.2 O 2 electrodes, the hybrid electrodes demonstrate a lower resistivity, smaller electrochemical polarization, stronger rate capability and stable capacity retention. Furthermore, Adding carbon aerogel into LiNi 0.6 Co 0.2 Mn 0.2 O 2 material is more conducive to enhancing the rate performance when compared with activated carbon. The lithium-ion full capacitor battery configured of a hard carbon anode and LiNi 0.6 Co 0.2 Mn 0.2 O 2 -carbon aerogel delivers a capacity of 97.3 mAhg−1 at 10C with an energy density reaching 323.8 Wh∙kg−1 (vs. the cathode), showing bright prospects in energy storage system with both high specific energy and power densities. [ABSTRACT FROM AUTHOR]