In this work, a simple and efficient spray pyrolysis process was developed in order to easily control the microstructure of carbon particles prepared from sucrose as a carbon source. The key idea of this work is to modify the sucrose-based aqueous spray solution with organic additives, polyethylene glycol (PEG) and carbohydrazide, as a structure-controlling agent. It was found that the use of both PEG and carbohydrazide as the organic additives makes it possible to produce carbon nanosheets similar to multi-layer graphene oxides. In addition, the organic additives were helpful for increasing the specific surface area of carbon powders. Carbon nanosheets had improved ion-sorption capacitance compared with porous carbon spheres with the filled morphology or the hollow structure due to the increase of ion-accessible surface area. From the electrochemical characterization, the carbon nanosheets with the structure like a graphene oxide, which could be successfully synthesized by the suggested new strategy, were revealed to be most profitable for electrode materials with high ion-sorption capacitance.