Enhancing lithium-ion battery kinetics and stability leveraging hybrid 1T/2H MoS2-graphene heterostructures

초록

The development of high-capacity and fast-charging anode materials is critical for the production of lithium-ion batteries (LIBs) for electric vehicles and energy storage systems. Molybdenum disulfide (MoS2) has attracted significant interest owing to its high theoretical capacity (similar to 670 mAh g(-1)), natural abundance, and low cost. However, its stable 2H phase suffers from poor electronic conductivity, while the highly conductive 1T phase is metastable, which limits its standalone application. To overcome these limitations, in this study we present a 1T/2H hybrid phase MoS2-graphene 2D heterostructure, synthesized through a scalable and efficient co-exfoliation process, which achieved a production of similar to 100 g per batch. This unique heterostructure benefits from an expanded interlayer spacing that enhances the Li-ion diffusion kinetics and reactivity, along with strong interfacial interactions with graphene that improve the conductivity and structural stability. Our anode material exhibited excellent electrochemical performance, delivering a specific capacity of similar to 565 mAh g(-1) at 0.5C after 100 cycles with similar to 93 % capacity retention. The material also showed high-rate stability, with similar to 97.5 % capacity recovery after fast charging at 3C and returning to 0.5C; even at 3C, it retained a remarkable capacity of similar to 469 mAh g(-1), highlighting its superior lithium storage capability under rapid charge/discharge conditions. Density functional theory (DFT) calculations revealed that the 1T/2H phase interface and the graphene matrix synergistically enhanced the Li-ion intercalation and diffusion, significantly reducing the diffusion barrier (similar to 0.19 eV). This study provides critical insights into the interfacial interactions governing high-performance, fast-charging MoS2-based anodes, opening a promising avenue for next-generation energy storage technologies.

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