Exfoliated MoS<sub>2</sub> Nanosheet/Cellulose Nanocrystal Flexible Composite Films as Electrodes for Zinc Batteries
Amit Kumar Sonker, Shizhao Xiong, Ruchi Aggarwal, Martina Olsson, Arnita Spule, Seyedehsan Hosseini, Sumit Kumar Sonkar, Aleksandar Matic, Gunnar Westman
Abstract
High Resolution Image Download MS PowerPoint Slide The study presents a more efficient way of exfoliating MoS 2 in water and the exfoliated MoS 2 was used in an electrode. The electrodes were prepared from exfoliated MoS 2 (active material)–nanocrystalline cellulose (binder) with carbon nanotubes (electron-conducting support) and demonstrated in a zinc battery half-cell that showed a Coulombic efficiency of 90%. Successful exfoliation of MoS 2 was done by sonication of bulk MoS 2 with sulfated cellulose nanocrystals (CNC) for 4 h. The exfoliation was confirmed by Raman and transmission electron microscopy; interestingly, the Raman signals for exfoliated MoS 2 show a blue shift for both A 1g and E 2g 1 bands, which may be an indication of an induced lattice strain effect from the CNC on MoS 2 . The resulting stable water suspension showed no tendency of precipitation after 2 months of standing. The zeta potential, ζ, for sodium sulfated CNC (CNC–OSO 3 Na)–MoS 2 in water suspension was −45 mV, whereas sulfated CNC (CNC–OSO 3 H)–MoS 2 in water suspension had a zeta potential of −35 mV. The sodium form of sulfated CNCs displayed micelle characteristics, similar to sodium dodecyl sulfate (SDS), with a critical aggregation concentration (CAC) of 1.1 wt %. At CAC, the CNCs efficiently exfoliated MoS 2, which is at a much lower concentration than has been reported for synthetic surfactants like SDS and cetyl trimethyl ammonium bromide.