Biomass-derived graphene-like materials as active electrodes for supercapacitor applications: A critical review

•78% of works use phytomass as precursor of graphene-like carbon.•98% of works employ pyrolysis-activation for graphene-like material synthesis.•Raman fingerprint does not conform to graphene in the majority of studies.•Optimum performance for ID/IG ratio in the range of 0.8–1.•Specific surface area above a certain value does not enhance performance. Research studies on biomass derived graphene-like carbon materials for use in novel energy storage applications, has increased significantly in the last decade. It is a promising approach to a more sustainable energy future, as the synthesis of graphene-like structures from biomass is cost-effective and almost carbon neutral. In addition, they are ideal candidates for carbon-based supercapacitor devices, which are considered to be the key for future electrification ofgreen transportation, because of their sustainability and excellent performance at high-power and short-term demands of energy. Here, in this short-review of 51 studies resembling the above criteria (biomass derived graphene-like electrodes for supercapacitors), we attempt to evaluate the quality of these “graphene or graphene-like” structures based on Raman scattering data provided. The evaluation of performance in terms of specific capacitance in relation to the specific surface area (SSA), porosity and Raman characteristics of each material is also discussed. Hetero-atoms (mainly O and N) effect on performance is also analyzed solely and in conjunction with SSA.