Coal-Based Semicoke-Derived Carbon Anode Materials with Tunable Microcrystalline Structure for Fast Lithium-Ion Storage

Abstract

Fast charging capability is highly desired for new generation lithium-ion batteries used in consumer-grade electronic devices and electric vehicles. However, currently used anodes suffer from sluggish ion kinetics due to limited interlayer distance. Herein, the coal-based semicoke was chosen as precursor to prepare cost-effective carbon anodes with high-rate performance through a facile pyrolytic strategy. The evolution of microstructure and its effect on electrochemical performance are entirely studied. The results show that large number of short-ordered defective structures are generated due to the occurrence of turbostatic-like structures when pyrolyzed at 900 °C, which are propitious to large interlayer distance and developed porous structure. High accessible surface area and large interlayer spacing with short-ordered defective domains endow the sample treated at 900 °C under argon (A900) with accelerated ion dynamics and enhanced ion adsorption dominated surface-induced capacitive processes. As a result, A900 delivers high capacity (331.1 mAh g−1 at 0.1 A g−1) and long life expectancy (94.8% after 1000 cycles at 1 A g−1) as well as good rate capability (153.2 mAh g−1 at 5 A g−1). This work opens a scalable avenue to fabricating cost-effective, high-rate, and long cycling life carbon anodes.

Keywords

• semicoke
• carbon anode
• turbostatic phase
• short-ordered defective structures
• large interlayer spacing
• fast lithium storage