Borate-Based Compounds as Mixed Polyanion Cathode Materials for Advanced Batteries.

Rational design of new and cost-effective advanced batteries for the intended scale of application is concurrent with cathode materials development. Foundational knowledge of cathode materials' processing−structure−properties−performance relationship is integral. In this review, we provide an overview of borate-based compounds as possible mixed polyanion cathode materials in organic electrolyte metal-ion batteries. A recapitulation of lithium-ion battery (LIB) cathode materials development provides that rationale. The combined method of data mining and high-throughput ab initio computing was briefly discussed to derive how carbonate-based compounds in sidorenkite structure were suggested. Borate-based compounds, albeit just close to stability (viz., <30 meV at−1), offer tunability and versatility and hence, potential effectivity as polyanion cathodes due to (1) diverse structures which can host alkali metal intercalation; (2) the low weight of borate relative to mature polyanion families which can translate to higher theoretical capacity; and a (3) rich chemistry which can alter the inductive effect on earth-abundant transition metals (e.g., Ni and Fe), potentially improving the open-circuit voltage (OCV) of the cell. This review paper provides a reference on the structures, properties, and synthesis routes of known borate-based compounds [viz., borophosphate (BPO), borosilicate (BSiO), and borosulfate (BSO)], as these borate-based compounds are untapped despite their potential for mixed polyanion cathode materials for advanced batteries.

High on/off ratio field effect transistors based on exfoliated crystalline SnS2 nano-membranes.

We report the implementation of field effect transistors based on exfoliated nano-membranes of a layered two-dimensional semiconductor SnS(2), which exhibit an on/off ratio exceeding 2 × 10(6) and a carrier mobility of ∼1 cm(2) V(-1) s(-1). The results demonstrate the great potential of SnS(2), a layered semiconductor with finite band gap, as the building block for future nanoelectronic applications complementary to graphene-based materials with zero or small band gaps.