Unstable solid electrolyte interface and sluggish kinetics due to the high solubility and low ionic/electronic conductivity are the main issues for organic materials applied in nonaqueous metal-ion batteries, despite their diversity, property tunability and environmental friendliness. Here, an anion engineering in solid organic materials of cobalt polyphthalocyanine (CoPPc) for lithium-ion storage is proposed and explored strategically to tailor the electrochemically forming process of the solid-state interface (SEI) films to resist the solubility of the organic active center. To achieve the target, Trioctylphosphine oxide (TOPO) was introduced into CoPPc. The results demonstrate that the incorporation of TOPO into CoPPc could dramatically influence the adsorption of PF? 6 groups on the surface of the CoPPc electrode, resulting in the formation of uniform and robust SEI films and the enhancement of the reversible capacity. The anion-engineered CoPPc electrode delivers a reversible capacity of 986.3 mAh g?1 after 200?cycles at 200?mA?g?1 with an apparent capacity increment of 35.9?%. In addition, the anion-engineered CoPPc electrode maintained a high stability capacity of 690.8 mAh g?1 after 1000?cycles at 1 A g?1, showing exceptional rate capability and long-term cycling stability. Our theoretical simulations further demonstrate that the shortening of the CoN bond changes the electronic distribution in CoPPc and thus induces the preferential adsorption of PF? 6 groups. In addition, the weakening of the CoN bond energy strengthens the reversibility of the cobalt ions. This work provides a new anion-engineering strategy for developing organic electrode materials for LIBs with high-capacity and long-term cycling stability.

https://authors.elsevier.com/a/1mNMu5bbJ5uxfN

https://doi.org/10.1016/j.jelechem.2025.119773