Synergistic Modulation of HOMO Energy Level and Electronic Structure in Phthalates Anodes Active Materials Enables High‐Performance of Li‐Ion Batteries

Abstract

Abstract This study employs molecular engineering to modulate HOMO levels and electronic structures, designing high‐performance phthalate‐based anodes (ZnPA, CaPA, CuPA) to address challenges like limited capacity and poor cycling in organic lithium‐ion batteries. CuPA delivers 749 mAh g −1 after 100 cycles at 0.1 A g −1 and retains 200 mAh g −1 after 2500 cycles at 1 A g −1 . ZnPA achieves 650 mAh g −1 at 0.1 A g −1 and maintains 200 mAh g −1 after 1500 cycles at 1 A g −1 . CaPA shows increased capacity at higher current (197 mAh g −1 at 1 A g −1 ) due to (100) plane expansion. Redox mechanisms differ: CuPA and ZnPA carbonyl group facilitates lithium storage by a reversible enolization reaction, while the activated benzene ring exhibits redox activity for reversible lithiation/delithiation, with Cu 2+ irreversibly reducing to Cu⁺, while Zn 2+ remains stable. CaPA enables efficient lithium storage by the reversible intercalation and deintercalation of lithium ions on its (100) crystallographic plane. Full cells with LiFePO 4 exhibit excellent performance: CuPA||LFP and ZnPA||LFP retain over 50% capacity after 1000 cycles; CaPA||LFP shows outstanding rate capability (103 mAh g −1 at 4C). This work demonstrates that molecular structural engineering is an effective strategy for enhancing organic electrode materials.