The intercalation chemistry of H2V3O8 nanobelts synthesised by a green, fast and cost-effective procedure

► H2V3O8 nanobelts synthesised in just 2 h. ► Electrochemical properties of as prepared H2V3O8 similar to samples prepared by more expensive routes. ► EELS experiments show full reduction to V3+. ► Extra capacity can be obtained down to 1 V but of little practical use. ► Remarkable stability of a protonated compound upon intercalation.