Elastomer nanocomposites containing MXene for mechanical robustness and electrical and thermal conductivity.

A novel 2D nanomaterial, Ti3C2Tx MXene, added conductivity and reinforcement to a common elastomer, nitrile butadiene rubber (NBR). X-ray diffraction revealed the intercalation of lithium ions and elastomer chains into the MXene interlayer spacing, which enabled exfoliation in the elastomer. The reaction between MXene and NBR was proved by a stepwise Fourier transform infrared spectroscopy. With increase in MXene fractions, electrical and thermal conductivity of the composite increased to 9 × 10-5 S cm-1 and 0.69 W m-1 K-1, respectively. At only 2.8 vol% MXene, a swelling ratio of 1.61 was achieved, representing a 75% reduction compared to NBR containing either graphene or carbon nanotubes at the same filler fraction. Tensile tests showed that with the increase in MXene content, Young's modulus increased while both tensile strength and elongation at break first increased and then decreased. Overall, latex compounding proved to be an efficient technique for forming NBR/MXene nanocomposites. The revealed reaction between MXene and NBR to create functional polymer nanocomposites could provide a platform for utilising MXene for other polymers.

Hydrogen Bonding-Reinforced Hydrogel Electrolyte for Flexible, Robust, and All-in-One Supercapacitor with Excellent Low-Temperature Tolerance.

Flexible supercapacitors are promising energy storage devices for emerging wearable electronics. However, due to the poor mechanical strength, complicated device manufacturing process, and unsatisfactory low-temperature tolerance, their overall performance for practical applications is hindered. Herein, we report a hydrogen bonding-reinforced, dual-crosslinked poly(vinyl alcohol), acrylic acid, and H2SO4 (PVA-AA-S) hydrogel electrolyte for all-in-one flexible supercapacitors. The PVA-AA-S hydrogel demonstrates excellent compressive/tensile properties and high ionic conductivity. It tolerates compressive stress of 0.53 MPa and is stretchable up to 500%. The hydrogel-based all-in-one supercapacitor shows promising electrochemical performance under various harsh conditions. The device energy density and power density reach up to 14.2 µWh cm-2 and 0.94 mW cm-2, respectively. Furthermore, it retains nearly 80% capacitance after being stored at -35 °C for 23 days. The excellent performance of the hydrogel electrolyte originates from its abundant strong hydrogen bonding between polymer chains and water molecules.