Copper tetrathiovanadate (Cu₃VS₄): a newly emerging electrode for rechargeable aqueous aluminum-ion batteries

We report the electrochemistry of Al3+ ion storage in copper tetrathiovanadate (Cu3VS4) in an aqueous electrolyte for the first time. It is found that Cu3VS4 could deliver an initial discharge capacity of 111 mA h g(-1) at a current rate of 0.5 A g(-1) and 77 mA h g(-1) up to the 300(th) cycle at 2 A g(-1) along with an excellent rate capability. The better electrochemical performance may be attributed to the high theoretical capacity of sulfur and the superior conductivity of copper which allows facile Al3+ ion diffusion in Cu3VS4. The electrochemical mechanism of Al3+ ion storage is also illustrated.