High-Performance Anode Material of Tert-Butyl-Modified Naphthalocyanine Based on Spatial-Electronic Dual-Regulation Mechanism

Abstract

Lithium-ion batteries (LIBs) can benefit from transition metal oxides as anode materials because of their high theoretical capacities. However, volume expansion during cycling restricts their application. In this study, cobalt phthalocyanine modified by tert-butyl groups (tBuCoNc), with "steric-electronic" dual regulation, is used. The tert-butyl groups serve as a bridge for molecular design and property optimization. The cobalt oxide/nitrogen-doped graphene composites are constructed. The conjugated planar structure enhances charge transport, while tert-butyl substituents provide steric hindrance that improves structural stability and prevents nanoparticle aggregation. Upon pyrolysis, cobalt centers are transformed into uniformly dispersed cobalt oxide nanocrystals within a nitrogen-doped carbon matrix, offering abundant active sites that facilitate ion diffusion and electrolyte contact. The final composite, formed via π-π stacking and thermal treatment, exhibits strong synergistic effects between cobalt oxide and N-doped graphene. Electrochemical testing reveals an impressive initial discharge capacity of 1556.5 mAh g^-1 at 100 mA g^-1 and 741.1 mAh g^-1 after 100 cycles, highlighting its potential as a high-performance anode material for next-generation LIBs.