A new system of lithium recycling is designed to recover Li from materials containing waste Li. This waste-to-lithium (WTL) system operates based on electrochemical reaction at room temperature using three functional sections: two cathode compartments, one for the waste materials and one for recycling the recovered Li, and one Li-harvesting anode compartment located between the two cathode compartments. By charging the system, Li ions from waste Li-containing materials are extracted and converted into Li metal in the harvesting anode compartment. The harvested Li metal can be transformed via electrochemical reactions with water into useful Li precursors such as LiOH and Li2CO3, which are commonly used Li source chemicals. The concept of the WTL system is proved using well-known cathode materials from Li ion batteries and a commercial Li ion battery pack as the waste Li-containing materials. The harvested Li metal shows a purity of ∼99%, and the produced Li2CO3 is phase-pure without any notable secondary phase. Compared to existing Li recycling technologies, which are generally complicated, time-consuming chemical and heating processes, the WTL system is straightforward and can be operated at room temperature without using any deleterious acid chemicals, thus opening a new avenue for cost-effective, eco-friendly Li-recycling systems.