<p>Existing lithium-ion battery recycling methods often involve energy-, chemical- and/or waste-intensive processes. Here we demonstrated a self-looped electrochemical battery recycling approach that enables efficient recycling of lithium and transition metals from spent cathode materials. These recycled materials can be directly applied to manufacture new batteries without further treatment. By operating electrochemical hydrogen evolution and oxidation reactions in a three-chamber porous solid electrolyte reactor, input Li₂SO₄ solution can be converted into lithium hydroxide and sulfuric acid with a Li⁺ transport efficiency of around 90%, at current densities of 100 mA cm⁻² and low energy consumption (starting from 0.36 V). This is followed by a stoichiometric acid leaching and alkaline precipitation process that separates spent lithium metal oxides into high-purity (&gt;99.7%) lithium and transition metal hydroxide products. The Li₂SO₄ solution can be successfully restored at the end of each recycling cycle, enabling a sustainable process that requires only H₂O₂ as an external input. This approach avoids external cation contamination and eliminates the need for waste stream treatments.</p><p></p>