Lithium-ion batteries have shown promising performance in high-energy storage systems for electric vehicles. The electrode material used in the battery affects the performance of the LIB. The material on the anode can be modified by adding activated carbon (AC) to the graphite. AC can be made from a variety of biomass wastes, including black betel leaf biomass. AC was prepared by hydrothermal carbonization method in an inert gas atmosphere and then activated with a KOH solution. AC material was then analyzed by SEM and FTIR. Li-ion batteries with 0%, 10%, and 20% activated carbon addition were tested with a battery analyzer. The resulting specific capacities of graphite-AC 0%, graphite-AC 10%, and graphite-AC 20% batteries were 115.57 mAh/g, 94.60 mAh/g, and 76.38 mAh/g, respectively. The battery was then cycle tested at a current of 0.5C, and the resulting battery with the addition of 20% activated carbon showed the best retention capacity of 88.34% after 50 cycles. The battery test results show that activated carbon from black betel leaves can be used as an anode material for lithium-ion batteries.