posted on 2023-05-15, 15:11authored byAmit Kumar Sonker, Shizhao Xiong, Ruchi Aggarwal, Martina Olsson, Arnita Spule, Seyedehsan Hosseini, Sumit Kumar Sonkar, Aleksandar Matic, Gunnar Westman
The study presents
a more efficient way of exfoliating
MoS2 in water and the exfoliated MoS2 was used
in an
electrode. The electrodes were prepared from exfoliated MoS2 (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 MoS2 was done by sonication of
bulk MoS2 with sulfated cellulose nanocrystals (CNC) for
4 h. The exfoliation was confirmed by Raman and transmission electron
microscopy; interestingly, the Raman signals for exfoliated MoS2 show a blue shift for both A1g and E2g1 bands, which
may be an indication of an induced lattice strain effect from the
CNC on MoS2. The resulting stable water suspension showed
no tendency of precipitation after 2 months of standing. The zeta
potential, ζ, for sodium sulfated CNC (CNC–OSO3Na)–MoS2 in water suspension was −45 mV,
whereas sulfated CNC (CNC–OSO3H)–MoS2 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
MoS2, which is at a much lower concentration than has been
reported for synthetic surfactants like SDS and cetyl trimethyl ammonium
bromide.