Semi-coke-based amorphous porous carbon synthesized by a molten salt assisted method for superior lithium storage

Abstract

Amorphous porous carbon with a network structure composed of nanosheets was prepared from semi-coke by a facile molten salt method. The low-melting eutectic salts act as solvents at 600 °C, and the porous carbon was obtained in a liquid reaction environment. Meanwhile, the effects of temperature on morphology and electrochemical performance of the carbon materials were studied. The electrodes exhibit extraordinary electrochemical performance as anodes for lithium-ion batteries and show a high capacity of 539.9 mA h g⁻¹ at 0.2 A g⁻¹ after 150 cycles. Moreover, the medium surface area of carbon nanosheets contributes to the high initial Coulombic efficiency of 72.9%. More importantly, the sample shows an excellent cyclability of 231.1 mA h g⁻¹ at 2 A g⁻¹ after 500 cycles. The superior electrochemical performance can be attributed to the unique structure accelerating the movement of electrons/ions and the permeation of the electrolyte, and the cross-linked network structure shortening the Li⁺ migration path. This method is simple, environmentally friendly, and has broad application prospects in the preparation of carbon-based anode materials.