Nitrogen-Doped Porous Carbon Derived from Coal for High-Performance Dual-Carbon Lithium-Ion Capacitors

Abstract

Lithium-ion capacitors (LICs) are emerging as one of the most advanced hybrid energy storage devices, however, their development is limited by the imbalance of the dynamics and capacity between the anode and cathode electrodes. Herein, anthracite was proposed as the raw material to prepare coal-based, nitrogen-doped porous carbon materials (CNPCs), together with being employed as a cathode and anode used for dual-carbon lithium-ion capacitors (DC-LICs). The prepared CNPCs exhibited a folded carbon nanosheet structure and the pores could be well regulated by changing the additional amount of g-C3N4, showing a high conductivity, abundant heteroatoms, and a large specific surface area. As expected, the optimized CNPCs (CTK-1.0) delivered a superior lithium storage capacity, which exhibited a high specific capacity of 750 mAh g−1 and maintained an excellent capacity retention rate of 97% after 800 cycles. Furthermore, DC-LICs (CTK-1.0//CTK-1.0) were assembled using the CTK-1.0 as both cathode and anode electrodes to match well in terms of internal kinetics and capacity simultaneously, which displayed a maximum energy density of 137.6 Wh kg−1 and a protracted lifetime of 3000 cycles. This work demonstrates the great potential of coal-based carbon materials for electrochemical energy storage devices and also provides a new way for the high value-added utilization of coal materials.

Transforming Waste into Wealth: Advanced Carbon-Based Electrodes Derived from Refinery and Coal By-Products for Next-Generation Energy Storage

“…After 3000 cycles, they showed a high-capacity ratio of 75% at a current density of 2 A/g. This indicated their outstanding cyclic stability [80].…”

“…The porous and linked carbon nanosheets allowed for a significant specific surface area to be in contact with the electrolyte. At the same time, the nitrogen-doping structure provided additional active sites for Li + adsorption and pseudocapacitance [80]. A two-step heat treatment process created oxygen self-doped hierarchical porous carbons (OHPCs) utilizing KOH as the activation agent and CLR as the raw material.…”