Bio-inspired beehive-like hierarchical nanoporous carbon (BHNC) with a high specific surface area of 1472 m 2 g -1 and a good electronic conductivity of 4.5 S cm -1 is synthesized by carbonizing the industrial waste of bamboo-based byproduct. The BHNC sample exhibits remarkable electrochemical performances as supercapacitor electrode material such as high specific capacitance of 301 F g -1 at 0.1 A g -1 still 10 maintaining that of 192 F g -1 at 100 A g -1 , negligible capacitance loss after 20,000 cycles at 1 A g -1 , and high power density of 26,000 W kg -1 at energy density of 6.1 Wh kg -1 based on active electrode materials in aqueous electrolyte system. Moreover, an enhanced power density of 42,000 W kg -1 at high energy density of 43.3 Wh kg -1 is obtained in ionic liquid electrolyte system, which places the BHNC-based supercapacitors in the Ragone chart among the best energy-power synergetic outputting properties in ever 15 reported for carbon-based supercapacitors.

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Two-dimensional (2D) porous carbon AC-SPN-3 possessing of amazing high micropore volume ratio of 83% and large surface area of about 1069 m2 g−1 is high-yield obtained by pyrolysis of natural waste Pistachio nutshells with KOH activation. The AC-SPN-3 has a curved 2D lamellar morphology with the thickness of each slice about 200 nm. The porous carbon is consists of highly interconnected uniform pores with the median pore diameter of about 0.76 nm, which could potentially improve the performance by maximizing the electrode surface area accessible to the typical electrolyte ions (such as TEA+, diameter = ~0.68 nm). Electrochemical analyses show that AC-SPN-3 has significantly large areal capacitance of 29.3/20.1 μF cm−2 and high energy density of 10/39 Wh kg−1 at power of 52/286 kW kg−1 in 6 M KOH aqueous electrolyte and 1 M TEABF4 in EC-DEC (1:1) organic electrolyte system, respectively.

Renewable graphene-like nitrogen-doped carbon nanosheets were constructed from layered shrimp shells with integrated high energy–power supercapacitive properties.

A facile synthesis of an MnO/C nanocomposite material consisting of 5.3 wt% of MnO on the surface of porous carbon is introduced.