Zinc terephthalates ZnC₈H₄O₄ as anodes for lithium ion batteries

Graphical abstract: Both of well-crystalline and amorphous zinc terephthalates ZnC₈H₄O₄ are synthesized and amorphous structure demonstrates a higher capacity and better cycling performance. - Highlights: • Crystalline and amorphous ZnC₈H₄O₄ are obtained. • Both crystalline and amorphous ZnC₈H₄O₄ have σ_e of 10⁻⁷ S m⁻¹. • Lithium ion diffusion is the rate-determine process. • Amorphous has a high capacity and durable performance. • Amorphous ZnC₈H₄O₄ has a high apparent lithium ion diffusion coefficient. - Abstract: Organic materials offer the advantages of cost-effective, environmental benignity, and molecular structural diversity as applications of electrode materials for lithium ion batteries. In fact, their lithium storage behaviors in terms of dynamics and kinetics intrinsically lie in ion migration in solids. Thus the solid forms including crystalline and amorphous states are crucial for the properties. In this study, a conventional carbonyl type organic material, namely zinc terephthalate (ZnC₈H₄O₄), is obtained in both well-crystalline and amorphous forms and applied as anodes for lithium ion batteries. ZnC₈H₄O₄ with amorphous structure shows higher lithium storage capacity and better capacity retention compared with that of crystalline one. It is ascribed that the amorphous phase provides a higher lithium ion diffusion coefficient than the crystalline one under the conditions of similar electronic conductivity.