Al3+ ion storage in LiMnPO4 for rechargeable aqueous aluminum-ion battery

•Al3+ ion insertion in LiMnPO4 is illustrated for the first time.•The initial Al3+ ion storage capacity of LiMnPO4 is 146 mAhg−1.•A rechargeable aqueous Al3+ ion cell is demonstrated with LiMnPO4 as cathode and WO3 as anode. Herein, we demonstrate the Al3+ ion electrochemical activity of LiMnPO4 in aqueous electrolyte. It is found that LiMnPO4 can store Al3+ ion and it possesses two discharge plateaus at 1.09 V and 0.86 V (vs Ag/AgCl). The initial discharge capacity is as high as 146 mAhg−1 at a current rate of 1 Ag−1 with capacity retention of 50 mAhg−1 over 450 cycles at current rate of 2.5 Ag−1. A functional rechargeable aqueous Al3+ ion cell is also demonstrated with LiMnPO4 as cathode and WO3 as anode. The cell shows discharge plateau in the potential range of 1–1.4 V with excellent cycling stability.