High performance liquid crystalline bionanocomposite ionogels prepared by in situ crosslinking of cellulose/halloysite nanotubes/ionic liquid dispersions and its application in supercapacitors

A high performance halloysite nanotubes (HNTs)-doped liquid crystalline bionanocomposite ionogels has been synthesized by in situ crosslinking of cellulose/ionic liquid solutions using bisphenol A epoxy resin via ring opening reactions with cerium ammonium nitrate, and HNTs as the ionic conducing promoter. These ionogels with HNTs demonstrate significantly improved ionic conductivity compared with that of pure ionogel without the addition of HNTs, due to the liquid crystal phases induced by the assembly of anisotropic HNTs nanoparticles generated ionic channels for ion transport. The ionic conductivity of the ionogels increases with increasing HNTs concentration, and shearing can improve the room temperature ionic conductivities, which are on the order of 1 mS/cm. The mechanical properties and thermal stability of the nanocomposite ionogels were significantly improved compared with those of the pure ionogel without HNTs. The ionogel was tested as a flexible gel electrolyte for supercapacitor device and the measured specific capacitance was maintained for up to 5000 charge-discharge cycles. Such novel liquid crystalline bionanocomposite ionogels with high ionic conductivity, high mechanical strength, and flexibility are desirable for use in flexible electrochemical devices.