NbSe 2 Nanosheets/Nanorolls Obtained via Fast and Direct Aqueous Electrochemical Exfoliation for High-Capacity Lithium Storage.
Daniel F CarrascoSergio García-DalíSílvia Villar RodilJose M MunueraEncarnación Raymundo-PiñeroJuan Ignacio ParedesPublished in: ACS applied energy materials (2023)
Layered transition-metal dichalcogenides (LTMDs) in two-dimensional (2D) form are attractive for electrochemical energy storage, but research efforts in this realm have so far largely focused on the best-known members of such a family of materials, mainly MoS 2 , MoSe 2 , and WS 2 . To exploit the potential of further, currently less-studied 2D LTMDs, targeted methods for their production, preferably by cost-effective and sustainable means, as well as control over their nanomorphology, are highly desirable. Here, we report a quick and straightforward route for the preparation of 2D NbSe 2 and other metallic 2D LTMDs that relies on delaminating their bulk parent solid under aqueous cathodic conditions. Unlike typical electrochemical exfoliation methods for 2D materials, which generally require an additional processing step (e.g., sonication) to complete delamination, the present electrolytic strategy yielded directly exfoliated nano-objects in a very short time (1-2 min) and with significant yields (∼16 wt %). Moreover, the dominant morphology of the exfoliated 2D NbSe 2 products could be tuned between rolled-up nanosheets (nanorolls) and unfolded nanosheets, depending on the solvent where the nano-objects were dispersed (water or isopropanol). This rather unusual delamination behavior of NbSe 2 was explored and concluded to occur via a redox mechanism that involves some degree of hydrolytic oxidation of the material triggered by the cathodic treatment. The delamination strategy could be extended to other metallic LTMDs, such as NbS 2 and VSe 2 . When tested toward electrochemical lithium storage, electrodes based on the exfoliated NbSe 2 products delivered very high capacity values, up to 750-800 mA h g -1 at 0.5 A g -1 , where the positive effect of the nanoroll morphology, associated to increased accessibility of the lithium storage sites, was made apparent. Overall, these results are expected to expand the availability of fit-for-purpose 2D LTMDs by resorting to simple and expeditious production strategies of low environmental impact.
Keyphrases
- transition metal
- ionic liquid
- reduced graphene oxide
- gold nanoparticles
- molecularly imprinted
- solid state
- label free
- quantum dots
- electron transfer
- highly efficient
- room temperature
- visible light
- drug delivery
- human health
- magnetic resonance imaging
- hydrogen peroxide
- solid phase extraction
- quality improvement
- risk assessment
- metal organic framework
- nitric oxide
- endoplasmic reticulum stress
- endoplasmic reticulum
- life cycle