Batteries; lithium sulphur batteries; flexible form batteries; batteries incorporating boron nitride nanotubes; battery components and materials for lithium ion, lithium metal and lithium air batteries; components and materials for metal and metal composite anodes and cathodes including anodes and cathodes containing lithium, sodium, aluminium or potassium (or a combination of those), for use in batteries and supercapacitors; materials and components for use in supercapacitors and hybrid supercapacitor/batteries