Conductive halloysite clay nanotubes for high performance sodium ion battery cathode

It is a practical challenge to find a cathode material for sodium ion batteries (SIBs) with high capacity and low cost. Here, conductive halloysite nanotubes (Hal) were synthesized by wrapping a layer of polypyrrole (PPy) via in situ polymerization as a potential cathode material for SIBs. By functionalization with PPy, the zeta potential of Hal changed from -28.5 mV to +30.1 mV, which showed excellent aqueous dispersion stability. HR-TEM and XPS results also demonstrated that a continuous conductive layer was formed around the tubes. By virtue of the good electrical conductivity and special tubular structure of Hal@PPy, it was applied as cathode for sodium ion battery. The Hal@PPy electrode could maintain a capacity of 126 mAh g-1 after 280 cycles at current density of 200 mA g-1, which suggested a high potential in energy storage fields.