Interfacial regulation of biomass-derived carbon towards high-performance supercapacitor

Interfacial regulation for carbon-based materials plays critical role for supercapacitive performance improvement and the strategies about introducing heteroatomic groups and tuning specific surface area can be proposed to effectively address the low specific capacitance issues. Thus, the approaches about activation treatment with nitric acid (APC-H800) and copper chloride (APC-C800) for biomass-derived carbon materials have been raised and systematically investigated. Consequently, though the above chemical activation treatment, the oxygen and nitrogen functional groups can be introduced for APC-H800. Meanwhile, the specific surface area of APC-C800 has been significantly increased. Significantly, the upper specific capacitance of 384 F g−1 and 423 F g−1 for APC-H800 and APC-C800 electrodes can be achieved at a current density of 1.0 A g−1, what matters more is that two symmetric devices offer superior energy density and desirable cycling stability (no decrease that occurs after 10,000 cycles) are successfully assembled by employing APC-H800 and APC-C800 electrodes, respectively. More significantly, desirable energy density about 11.18 Wh kg−1 and 12.5 Wh kg−1 at 249.98 W kg−1 and 250 W kg−1 have been achieved for the symmetric supercapacitor devices of APC-H800//APC-H800 and APC-C800//APC-C800. These modification strategies shed insight into the sensible design of a further stage of advanced art carbon electrodes for powerful performance supercapacitors.