Phospholipids, as additives for lithium batteries, enhance stability

Phospholipids are amphiphilic biomolecules explored as functional additives for lithium-ion battery electrolytes. Their unique molecular architecture containing both polar hydrophilic head groups and non-polar lipophilic hydrocarbon tails enables preferential adsorption at electrode-electrolyte interfaces, which improves the overall interfacial stability of battery systems.

When incorporated into liquid electrolytes, phospholipid molecules spontaneously accumulate on the surfaces of cathode and anode materials. Through coordination between polar head groups and active sites of electrode surfaces, they participate in constructing a uniform, dense and flexible interfacial film during battery formation cycles. This protective layer suppresses continuous side-reactions between electrolyte solvents and electrode materials, reducing irreversible decomposition of electrolyte components. It also restrains the excessive growth of unstable solid‑electrolyte interphase, lowering interfacial impedance accumulation upon long‑term cycling.

On anode sides, the adsorbed phospholipid-derived film buffers volume variation of electrode materials during lithium-ion insertion and extraction. It alleviates mechanical cracking of interfacial layers caused by volume expansion, and inhibits parasitic reactions that would consume active lithium. For high-voltage cathode materials, phospholipids can mitigate catalytic oxidation of electrolyte solvents at high potentials, restraining transition-metal dissolution from cathode lattices.

Appropriate additive dosage is critical for practical performance. Low phospholipid concentration fails to form a complete protective interface, while over-dosage may raise electrolyte viscosity, reduce ionic conductivity and increase cell internal resistance. Purified phospholipid fractions are selected to avoid residual impurities that trigger gas generation or capacity decay. As electrolyte functional additives, phospholipids contribute to prolonged cycle life and improved Coulombic efficiency, offering a new research direction for developing high-stable lithium-battery electrolyte systems.