(a) Graphic illustration of the fabrication process, (b–e) N 1s spectra, (f) graphic structure of the binding conditions of N and the mechanism of Na+
storage, (g) the content of nitrogen species, and (h) rate performance of shrimp skin-derived N-rich carbons [128
] (copyright 2017, Royal Society of Chemistry). (i) Graphic illustration of the preparation of oatmeal-derived N-doped carbon microspheres [129
] (copyright 2016, Elsevier).