Porous structure engineering of N-doped carbons for enhanced mass transfer towards High-Performance supercapacitors and Li-Ion batteries

Tailoring the porous structure of carbon materials is one essential approach to improve the energy storage performance of carbon-based electrode materials. Herein, hierarchical porous carbons (HPCs) with different meso-structure are synthesized via a one-pot pyrolysis process with SiO2 and ZnCl2 as template and activator, respectively. The energy storage capacities of the obtained HPC samples are investigated as bi-functional electrode both for supercapacitor and LIBs. The results show that different mesostructure of HPCs can effectively affect the energy storage performance. In the range of 15 ti 50 nm, smaller size of mesopore can result better electrochemical performance of HPCs. And the optimized HPC sample (HPC-15) manifests high specific capacitance of 432F g-1 and good cyclic stability in the supercapacitor application. When used as anode of LIBs, the HPC-15 presents a high capacity of 820 mAh g-1. In addition, COMSOL simulation is employed to study the effect of pore structure on mass transfer during electrochemical process. The HPC-15 is calculated to have the highest total porosity (ep) and effective diffusivity of K+ (De = 6.776 x 10-10 m2 s-1), thus leading to its best electrochemical performance.

Automated summary

This study synthesized hierarchical porous carbons with different meso-structure and investigated their energy storage performance in supercapacitors and LIBs. The results show that smaller mesopore size can effectively improve the energy storage performance. The optimized HPC sample exhibits high capacitance and stability in supercapacitor application, as well as a high capacity in LIBs.