PCBM-Functionalized WS₂-CNT Hybrid Nanostructures for Enhanced and Binder-Free Li-Ion Battery Anodes

Tungsten disulfide (WS₂), a promising transition metal dichalcogenide (TMD), has attracted considerable interest as a potential intercalation host material for lithium-ion batteries (LIBs). This interest is due to its distinctive graphite-like layered structure, high theoretical specific capacity of 433 mAh g^-1, cost-effectiveness, and excellent charge transport and mechanical properties [1]. However, WS₂-based anodes encounter several challenges, such as pulverization, low electronic and ionic conductivities, an unstable solid-electrolyte interphase (SEI) layer, and thermal runaway risks, which hinder their use in practical applications [2–4]. To address the technical challenges of WS₂-based anodes in LIBs. We demonstrate the effective functionalization of WS₂ nanoflakes and MWCNT (multiwalled carbon nanotube) bundles using the n-type semiconducting polymer PCBM (Phenyl-C₆₁-butyric acid methyl ester). This functionalization facilitates the formation of hybrid nanostructures, resulting in significantly enhanced performance of WS₂ anodes in LIB applications. PCBM served as a conductive bridge between the WS₂ hexagonal nanoflakes and the MWCNT bundles, effectively reducing junction resistance. Furthermore, PCBM functionalization helped prevent the agglomeration and pulverization of the WS₂ nanoflakes, ensuring better structural stability. The functionalization of WS₂ and MWCNTs with PCBM is confirmed by the FTIR and Raman spectroscopies. The demonstrated WS₂-PCBM/MWCNT hybrid nanostructures based anodes were cycled for 500 cycles at current density of 1.0 A g^-1, which has shown a stable average discharge specific capacity of ~485.73 mAh g^-1 with coulombic efficiency (CE) of ~100% [5]. In addition, the PVDF binder-free WS₂-PCBM/MWCNT hybrid nanostructure-based anode has displayed an average discharge specific capacities of ~1224 mAh g^-1 for up to 25 cycles at current density of 0.1 A g^-1 with CE of ~99.99%. Thus, our work opens new avenues for utilizing PCBM as a carbon conductor to enhance the performance of WS₂-based anodes in Li-ion and other metal-ion batteries. Furthermore, our findings provide an innovative and scalable approach for developing conventional binder-free electrodes.

References:

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