多孔炭对超级电容器电荷存储的影响

A review of charge storage in porous carbon-based supercapacitors

由于具有良好的物理化学稳定性、高比表面积、可调的孔结构及优良的导电性,多孔炭广泛应用于超级电容器电极材料。它的电容性能与其比表面积、孔结构、表面杂原子、结构缺陷及电极结构密切相关。离子及表面积(有效表面)能够提供丰富的活性位点,而合适的孔结构有利于离子的传输和存储,因而共同影响着炭基电极材料的比电容和倍率性能。具有合适孔径分布、一定数量的离子传输通道及微孔/介孔比例,是提高超级电容器能量密度和功率密度的必要条件。此外,结构缺陷、表面杂原子及合理的电极结构设计对多孔炭基超级电容器的电容性能具有重要的影响。

Porous carbon-based electrode materials have been widely used in supercapacitors(SCs)because of their good physicochemical stability,high specific surface area,adjustable pore structure,and excellent electrical conductivity.The factors influencing their SC performance are analyzed,which include specific surface area,pore structure,surface heteroatoms,structural defects and electrode structure.The high surface area accessible to ions provides abundant active sites for their storage,while a suitable pore structure is important for the accommodation and diffusion of ions,thereby influencing the specific capacitance and rate performance of the electrodes.An appropriate pore size with a narrow distribution is required to increase the volumetric energy density while mesopores are favorable for ion transport,so a good balance between micro and mesopore volumes is important to improve both the energy and power densities of the SCs.Structural defects,surface heteroatoms and a rational electrode structural design all play significant roles in the capacitance performance.