Wheat Bran Derived Carbon toward Cost-Efficient and High Performance Lithium Storage

Graphite is the mainstream anode material of commercial lithium-ion batteries, while its low theoretical capacity and short supply limit its application in the ever-increasing demand for high-capacity batteries. For carbonaceous anode materials, the small surface area can endow relatively high initial Coulombic efficiency, and large mechanical strength can endow good stability during long-term cycling. In this study, sustainable wheat bran was utilized to prepare cost-efficient carbon anode via carbonization. At the reaction temperature of 800 °C, the carbonized wheat bran displayed an optimal mixed phase of ordered graphite (provided high conductivity) and amorphous carbon (provided more active sites). Due to a distinctive honeycomb-shaped hexagon structure and a small surface area of 57 m2 g–1, the as-prepared carbon material could achieve initial Coulombic efficiency up to 85%. Such an anode material revealed a superior reversible capacity of 515 mAh g–1 and corresponding retention of 92% after 1000 charge/discharge cycles. Using LiNi0.5Co0.2Mn0.3O2 as the cathode, the full cell delivered a large areal capacity of 2.66 mAh cm–2 over 200 cycles, with a high cycling stability of 82%. With such high Coulombic efficiency, areal capacity, and capacity retention, the carbonized wheat bran is on par with state-of-the-art carbonaceous anode material. This work develops a scalable and effective strategy to synthesize high-performance and low-cost carbon anode.