Manipulating internal morphology and mesoporous in monodisperse carbon nanospheres for supercapacitor with organic electrolyte

The deliberate integration of monodisperse carbon nanospheres (MCS) with unique interior morphology and mesoporous plays a crucial role in supercapacitor , but its synthetic methodology is still difficult. Here, a layer-by-layer coating coupled nano-confined pyrolysis strategy is developed to manipulating internal morphology and mesoporous in MCS. This synthesis features the employment of polymethyl methacrylate nanospheres (PMMA) as hard template and in-situ activator, allowing the aggregation of phenolic resin and silica on PMMA, and forcing CO 2 and H 2 O generated by PMMA pyrolysis encapsulated in shell. The internal morphology can be achieved by tuning PMMA amount, and the mesoporous can be controlled by optimizing PMMA pyrolysis kinetics. The optimized hollow carbon bowl-like spheres (HCB) presents a higher capacitance of 140.5 F g −1 than carbon spheres of 10.0 F g −1 and hollow carbon spheres of 99.9 F g −1 at 0.1 A g −1 , confirming that the internal morphology can effectively increase capacitance. Moreover, the reinforced mesoporous in HCB induce capacitances increasing from 111.9 to 117.3 and 140.5 F g −1 , confirming that small mesopore is the main host for organic ions. The HCB-based supercapacitor presents a higher energy density of 30.5 Wh kg −1 at power density 337.5 W kg −1 in TEABF 4 and 61.6 Wh kg −1 at 175 W kg −1 in MeEt 3 NBF 4 , and excellent cycling stability. This work validates the feasibility of enhancing capacitance by designing internal morphology and mesoporous in MCS.