“…Various biomass precursors, such as cherry stone [95], fish scale [96], waste paper [97], water bamboo [98], flour [67], yeast cells [99], fallen leaves [100], pine-cone [101], pig bone [65], willow catkins [102], celtuce leaves [103], waste tea-leaves [104], sunflower seed shell [105], ginkgo shells [106], cow dung [107], silk [108], human hair [109] and sewage sludge [110], have been chemically converted into ACs for supercapacitors. For example, a honeycomblike carbon foam has been successfully derived from natural flour via KOH activation, which exhibited a large specific surface area of 1313 m 2 g −1 and a high specific capacitance of 473 F g −1 (Figure 6(a,b)).…”