摘要
Here, we evaluate the suitability of natural biowaste-derived carbon anodes for sodium-ion batteries (NIBs). Specifically, we utilize eco-friendly, renewable, low-cost coffee grounds (CGs) as precursors and KOH as an activating agent in the preparation of nanoporous carbon (NPC) anodes for NIBs. The relationship between pore size/surface area and the battery performance is discussed carefully. When tested, the sample CGNPC1-5 exhibits a high reversible capacity of about 223 mA h g-1 (50 mA g-1) with a capacity retention up to 92% at the 250th cycle and a high capacity of 141 mA h g-1 at 1 A g-1. Importantly, the rate test over a range of 0.05-2.5 A g-1 demonstrates the excellent reversibility of CGNPCs. The higher percentage of mesopores and macropores in samples CGNPC1-5 and CGNPC1-10 than those of CGNPC1-0 and CGNPC1-1 facilitates Na-ion transportation, thus exhibiting higher capacities even at high rates. In summary, CGNPCs are promising as sustainable carbonic anodes for NIBs not only owing to their low price and eco-friendly properties but also because of their good cycling stability and ideal rate performance.