Alkali Metalation Enables Natural Anthraquinone Derivatives as Sustainable Cathode Materials for Lithium‐Ion Batteries

Organic electrode materials (OEMs) derived from natural quinones can enable sustainable lithium-ion batteries (LIBs) if their dissolution-induced capacity fading in organic electrolytes and their conductivity issues are addressed. It is demonstrated that converting natural anthraquinones (AQs) into organic alkali-metalated salts effectively inhibits their dissolution in aprotic electrolytes. For this purpose, a solubility indicator (ΔMPI) is developed, which reliably guides the selection of compatible OEMs and electrolytes. The effect of alkali metalation (i.e., replacing ─OH with ─OM, M = Li, Na, K) on the physicochemical properties of AQs is revealed, and validate experimentally the suppressed dissolution and improved cyclic stability of metalated AQs. Finally, the issue of low conductivity is solved by the addition of carbon nanotubes (CNTs). The best device, potassiated 2,6-DHAQ with added CNTs (K₂(2,6-DHAQ@CNTs)), exhibits an excellent electrochemical performance, maintaining a capacity of 164 mAhg^-1 at 1 C after 500 cycles when using the electrolyte consisting of 1 m LiTFSI in triethylene glycol dimethyl ether ((1 m) LiTFSI-TEGDME). The prepared materials demonstrate competitive stability and capacity comparable to state-of-the-art inorganic cathode materials, combined with superior cost-effectiveness and sustainability, making them promising candidates for practical applications.