Wood outlasts graphite: revolutionary birch biomass-based carbon anodes for long-life lithium-ion batteries

Abstract

Here, we present carbon anode materials derived from birch biomass (BCAM) with hierarchical micro–mesoporous structure, largely amorphous carbon framework and abundant active sites for lithium storage and efficient ion-transport – prepared through phosphoric acid activation followed by high-temperature pyrolysis at 1000 °C. BCAM materials deliver a reversible capacity of 915 mA h g⁻¹ at 1C after 1000 cycles, maintain 412 mA h g⁻¹ after 2000 cycles at 2.5C, and retain 235 mA h g⁻¹ after 5000 cycles at 5C with ca. 100% coulombic efficiency. As for comparison, a cell made with commercial graphite as also tested, the results showed a reversible capacity of 365 mA h g⁻¹ at 1C after 400 cycles, a much lower capacity than that of BCAM anode material. Kinetic analysis indicates a substantial pseudocapacitive contribution, particularly at higher scan rates, which supports fast charge–discharge behavior. In addition, electrochemical impedance spectroscopy reveals low charge-transfer resistance and favorable lithium-ion diffusion kinetics. In total, these birch-derived carbons provide a steppingstone in robust, low-cost, and environmentally benign anode materials, and offer a promising route towards long-life time and sustainable lithium-ion batteries (LIBs).