For the first time, CaV6O16·3H2O (CVO), synthesized via a highly efficient and fast microwave reaction, is used as a cathode material for aqueous zinc-ion batteries. Ex situ X-ray diffraction confirms the structure of this material to be stable upon reversible Zn2+ intercalation, due to its large interlayer distance (8.08 Å). The pillaring effect of calcium makes the as-prepared CVO an excellent Zn2+ cation host.