Low-Cost Transformation of Biomass-Derived Carbon to High-Performing Nano-graphite via Low-Temperature Electrochemical Graphitization
Bishnu P. Thapaliya, Huimin Luo, Phillip Halstenberg, Harry M. Meyer, John R. Dunlap, Sheng Dai
Abstract
Graphite, an essential component of energy storage devices, is traditionally synthesized via an energy-intensive thermal process (Acheson process) at ∼3300 K. However, the battery performance of such graphite is abysmal under fast-charging conditions, which is deemed essential for the propulsion of electric vehicles to the next level. Herein, a low-temperature electrochemical transformation approach has been demonstrated to afford a highly crystalline nano-graphite with the capability of tuning interlayer spacing to enhance the lithium diffusion kinetics in molten salts at 850 °C. The essence of our strategy lies in the effective electrocatalytic transformation of carbon to graphite at a lower temperature that could significantly increase the energy savings, reduce the cost, shorten the synthesis time, and replace the traditional graphite synthesis. The resulting graphite exhibits high purity, crystallinity, a high degree of graphitization, and a nanoflake architecture that all ensure fast lithium diffusion kinetics (∼2.0 × 10–8 cm2 s–1) through its nanosheet. Such unique features enable outstanding electrochemical performance (∼200 mA h g–1 at 5C for 1000 cycles, 1C = 372 mA g–1) as a fast-charging anode for lithium-ion batteries. This finding paves the way to make high energy-density fast-charging batteries that could boost electromobility.