Synthesis of porous carbon materials derived from waste buttonwoods, pineapple peels, and lettuce leaves and comparison of the electrochemical performances for lithium-ion battery

The waste buttonwoods, pineapple peels, and lettuce leaves have been activated by KOH and carbonized through a high-temperature process. When used as the anode materials for lithium-ion battery, the activated buttonwoods (BWs), pineapple peels (PPs), and lettuce leaves (LLs) can display that the first discharge capacities of BWs, PPs, and LLs are 313.9 mAh g(-1), 296.6 mAh g(-1), and 674.5 mAh g(-1) and those of charge are 162.2 mAh g(-1), 129.0 mAh g(-1) and 357.2 mAh g(-1), respectively. After 200 cycles, their discharge capacities are 164.8 mAh g(-1), 96.1 mAh g(-1), and 209.6 mAh g(-1), respectively. In addition, the energy density of LLs is the highest among the three materials, while its capacity retention ratios are lower than those of BWs. It could be due to the high Si content of LLs, a honeycomb-like porous structure of BWs and high-specific surface area of BWs and LLs.