The multifunctional properties of 2D boron nitride nanoflakes (BNNFs) in gel polymer electrolytes (GPEs) are presented. A small addition (0.5 wt%) of BNNFs into the GPE substantially improves all the advantageous properties of the GPE including ionic conductivity, Li⁺ transference number, mechanical modulus, and dendrite-suppressing capability, thereby enabling high performance lithium metal batteries.

A series of composite polymer electrolytes were prepared using an organic/inorganic hybrid branched-graft copolymer (BCP) based on poly(ethylene glycol) methyl ether methacrylate (PEGMA) and 3-(3,5,7,9,11,13,15-heptaisobutylpentacyclo-[9.5.1.1^3,9.1^5,15.1^7,13]octasiloxane-1-yl)propyl methacrylate (MA-POSS) as the polymer matrix and poly(ethylene glycol)-grafted graphene oxide (PGO) as the filler material, and they were applied as solid-state polymer electrolytes (SPEs) for lithium-ion battery applications. The ionic conductivity of the composite polymer electrolyte containing 0.2 wt% of PGO (2.1 × 10⁻⁴ S cm⁻¹ at 30 °C) was found to be one order of magnitude higher than that of the BCP (1.1 × 10⁻⁵ S cm⁻¹ at 30 °C); the pristine polymer matrix, because of the larger amount of lithium salt, can be dissociated in the composite polymer electrolyte by Lewis acid–base interactions between the PGO and lithium salt. The thermal and mechanical stabilities of the composite polymer electrolytes were also improved by introducing PGO fillers and reasonable storage modulus values were maintained even at elevated temperatures up to 150 °C. All-solid-state battery performance was evaluated with the composite polymer electrolyte containing 0.2 wt% of PGO, resulting in superior cycle performance compared to that of the BCP due to the enhanced ionic conductivity as well as additional ion-conducting paths provided by the PGO fillers.

Polyamide reverse osmosis membranes containing carbon nanotubes with acidic groups (CNTa), graphene oxide (GO), and both CNTa and GO (CNTa–GO) were prepared by the interfacial polymerization of trimesoyl chloride solutions in hexane and m-phenylenediamine aqueous solutions containing carbon nanomaterials. All of the polyamide membranes containing the carbon nanomaterials showed considerably improved membrane performances, such as water flux, chlorine resistance, long-term durability, and mechanical properties, compared to the polyamide membrane without any of the carbon nanomaterials due to the advantageous properties of the CNT and GO as the filler materials. The largest improvement of membrane performances was observed in the polyamide membrane with CNTa–GO (the mixture of CNTa and GO). CNTa–GO can be more well-dispersed in the aqueous solution than the one-component carbon nanomaterials, such as CNTa and GO, due to the surfactant effects of GO, and then, the polyamide membrane with CNTa–GO can contain the largest amount of the carbon materials among the membranes and show the best membrane performances.