Coal tar pitch-derived porous carbon prepared in deep eutectic spinning solution via electrospinning for supercapacitor electrodes

Abstract

Developing a novel preparation strategy for the fabrication of high-performance porous carbon electrode materials is still the focus of current research. Herein, O/N doped coal tar pitch (CTP)-based porous carbon with a fishnet-like structure is prepared via the electrospinning technology. CTP is used as a carbon source and ChCl/phenol deep eutectic solvent (DES) is used as a spinning solution directly, and not any polymer is added. The complexes obtained by electrospinning are then activated by a small amount of K3C6H5O7 and get the porous carbon. Specifically, the DES has a specific viscosity and can be used not only as a solvent to improve the spinnability of CTP, but also as N source and act as a multifunctional solution. The electrospinning technology constructs the macropores and mesopores, while K3C6H5O7 can make micropores and even ultra-micropores in the prepared carbon material. Benefiting from the constructive hierarchical pore channels and abundant heteroatoms doping, the prepared porous carbon electrode possesses a high specific capacitance of 202 F g−1 even when reaching commercial loading. Simultaneously, a novel K3C6H5O7/glycol/acetonitrile DES gel electrolyte is synthesized, and an extended working voltage (2.2 V) can be achieved. The fabricated capacitor has large energy density of 23.9 Wh kg−1, and can still operate normally in a wide temperature range (-25 ∼ 100 °C). The multifunctionality of DES uncovers the feasibility of preparation of porous carbon using DES as the spinning solution directly, and may expect to prepare other carbon materials using the proposed strategy with different carbon precursors.