Graphene-analogues Boron Nitride nanosheets with ultrahigh ionic liquid uptake capacity as quasi-solid electrolytes

Inorganic nanoparticles are typically used as electrode materials in lithium batteries. However, to cope with the most challenge that solid electrolytes have low ionic conductivity at room or lower temperatures, here we show graphene-analogues boron nitride (g-BN) nanosheets absorbing a large quantity of ILs as a solid-like electrolyte. The layered g-BN nanosheets have very high specific surface area, and they could absorb the IL as much as 10 times of its own weight. The ionic conductivity of the solid-like electrolyte is 3.85×10-3 S cm-1 at 25 °C, even though at -20 °C it still reaches 2.32×10-4 S cm-1, which are very close to that of the ionic liquid electrolytes. The high ionic conductivity is attributed to ordered lithium ion transport channels within g-BN nanolayers which are formed as the IL solution fills in. Furthermore, the electrolyte displays outstanding electrochemical properties and battery performance. This work opens up a new field for the application of layered nanomaterials in energy conversion devices.