Replacing flammable organic liquid electrolytes with solid Li-ion conductors is a promising approach to realize safe rechargeable batteries with high energy density. Composite solid electrolytes, which are comprised of a polymer matrix with ceramic Li-ion conductors dispersed inside, are attractive, since they combine the flexibility of polymer electrolytes and high ionic conductivities of ceramic electrolytes. However, the high conductivity of ceramic fillers is largely compromised by the low conductivity of the matrix, especially when nanoparticles (NPs) are used. Therefore, optimizations of the geometry of ceramic fillers are critical to further enhance the conductivity of composite electrolytes. Here we report the vertically aligned and connected LiAlTi(PO) (LATP) NPs in the poly(ethylene oxide) (PEO) matrix to maximize the ionic conduction, while maintaining the flexibility of the composite. This vertically aligned structure can be fabricated by an ice-templating-based method, and its conductivity reaches 0.52 × 10 S/cm, which is 3.6 times that of the composite electrolyte with randomly dispersed LATP NPs. The composite electrolyte also shows enhanced thermal and electrochemical stability compared to the pure PEO electrolyte. This method opens a new approach to optimize ion conduction in composite solid electrolytes for next-generation rechargeable batteries.
In this study, few-layered MoS2 nanosheets (MoS2-NS) were obtained via the top-down exfoliation method from bulk MoS2 (MoS2-Bulk), and the dielectric properties and microwave absorption performance of MoS2-NS were first reported. The dimension-dependent dielectric properties and microwave absorption performance of MoS2 were investigated by presenting a comparative study between MoS2-NS and MoS2-Bulk. Our results show that the imaginary permittivity (ε'') of MoS2-NS/wax is twice as large as that of MoS2-Bulk/wax. The minimum reflection loss (RL) value of MoS2-NS/wax with 60 wt% loading is -38.42 dB at a thickness of 2.4 mm, which is almost 4 times higher than that of MoS2-Bulk/wax, and the corresponding bandwidth with effective attenuation (<-10 dB) of MoS2-NS/wax is up to 4.1 GHz (9.6-13.76 GHz). The microwave absorption performance of MoS2-NS is comparable to those reported in carbon-related nanomaterials. The enhanced microwave absorption performance of MoS2-NS is attributed to the defect dipole polarization arising from Mo and S vacancies and its higher specific surface area. These results suggest that MoS2-NS is a promising candidate material not only in fundamental studies but also in practical microwave applications.
Molybdenum disulfide (MoS 2 ) has been proved to be a potential electromagnetic wave (EMW) absorber. However, the limited EMW attenuation mechanisms and conductivity have always been recognized as the major challenges impeding their further developments. In this study, a new dielectric tuning strategy giving rise to high EMW attenuation performance by manipulating phase content (with 0, 24, 50, and 100 wt% 1T phase) toward MoS 2 is demonstrated. The greatly introduced 2H/1T interfaces facilitate the dipole distribution dynamics, and the metal-semiconductor mixed phase enhances the electron transfer ability. Benefiting from the structural merits, the MoS 2 with 50 wt% 1T absorber delivers the maximum reflection loss of −45.5 dB and effective absorbing bandwidth of ≈3.89 GHz, corresponding to nearly ten times higher than that of pure 2H counterpart. Moreover, the Computer Simulation Technology (CST) simulation and Lorentz transmission electron microscope are performed to visualize the structural advantages of MoS 2 absorbers with mixed 2H/1T phases. By manipulating the phase compositions, this study provides a deep understanding and opens an avenue in developing efficient and high performance transition metal dichalcogenides (e.g., WS 2 , MoSe 2 , and WSe 2 ) absorbers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.