Figure 11.

(a) Morphology of the hollow microporous carbon spheres prepared from starch via a multi-step pyrolysis method and their cycling performance at 0.1 C [97]. Reprinted with permission from Ref. [97]. Copyright 2017 American Chemical Society. (b) The TEM image of nitrogen–sulfur co-doped carbon materials prepared from soluble starch via a template method [98]. Reprinted with permission from Ref. [98]. Copyright 2012 Royal Society of Chemistry (The scale bar represents 20 nm). (c) Photograph of the crude soybean biomass and the TEM image of the nitrogen–oxygen co-doped porous carbon materials prepared by using soybean as a precursor [100]. Reprinted with permission from Ref. [100]. Copyright 2016 Royal Society of Chemistry. (d) The photograph of the rice before and after expansion treatment, as well as the photograph of the nickel-doped hybrid carbon prepared based on the expansion technology and calcination [99]. Reprinted with permission from Ref. [99]. Copyright 2017 WILEY-VCH.