A Selective Etching Approach to Pore Structure Control of Polymeric Precursor: Creating Hierarchical Porous N, P Co-doped Carbon Nanospheres For Semi-Solid-State Supercapacitor
In this work, utilizing the dynamic imine exchange, we develop a selective etching strategy to construct porous polymer nanosphere precursors, which can be subsequently carbonized into hierarchical porous carbon nanospheres (PCNPs) co-doped with both N and P elements. Our strategy to polymer precursor is simple, suitable to various aldehyde and amino building blocks and easy to incorporate heteroatoms into the carbon matrix. Importantly, by simply adjust the concentration of etching agent, PCNPs with micro, meso-pores or even hollow structure can be controllably fabricated. The as prepared PCNPs exhibit excellent electrochemical performance with the highest specific capacitances of 359.5 F g -1 at 0.5 A g -1 and 224.0 F g -1 at 20 A g -1 in acid condition (1M H2SO4 ). The cycling stability of the PCNPs is also attractive, with a capacitance retention of ~95 % after 5000 cycles. Semi-solid-state supercapacitors assembled using PCNPs as electrodes and H2SO4 /PVA as a gel electrolyte, exhibit specific capacitances up to 226.7 F g -1 at 0.2 A g -1 and 126.0 F g -1 at and 20 A g -1 .