PNNL

Abstract

Two-dimensional (2D) "graphene-like" inorganic materials, because of the short lithium ion diffusion path and unique 2D carrier pathways, become a new research focus of the lithium storages. Some "graphene-like" binary compounds, such as, MnO2, MoS2 and VO2 ultrathin nanosheets, have been synthesized by a peeling method, which also exhibit enhanced lithium storage performances. However, it still remains a great challenge to synthesize widely-used lithium-containing ternary oxides with "graphene-like" nanostructures, because the lithium-containing ternary oxides, unlike ternary layered double hydroxides (LDH), are very hard to be directly peeled. Herein, we successfully synthesized ultrathin Li3VO4 nanoribbons with a thickness of about 3 nm by transformation from ultrathin V2O5•xH2O nanoribbons, moreover, we achieved the preparation of ultrathin Li3VO4 nanoribbon@graphene sandwich-like nanostructures (LVO/G) through a layer-by-layer assembly method. The unique sandwich-like nanostructures shows not only a high specific reversible capacitance (up to 452.5 mA h•g-1 after 200 cycles) but also an excellent cycling performance (with more than 299.2 mA h•g-1 of the capacity at 10 C after 1000 cycles) as well as very high rate capability. Such template strategy, using "graphene-like" binary inorganic nanosheets as templates to synthesize lithium-containing ternary oxide nanosheets, may be extended to prepare other ternary oxides with "graphene-like" nanostructures