Silver vanadium bronze, β-Ag0.33V2O5: crystal-water-free high-capacity cathode material for rechargeable Ca-ion batteries

After the initial activation process, the tunnel-type β-Ag 0.33 V 2 O 5 material exhibits a reversible capacity of 179 mA h g −1 at ∼2.8 V ( vs. Ca 2+ /Ca), the highest capacity among the Ca cathode materials without crystal water reported to date.