A new perylene-based tetracarboxylate as anode and LiMn2O4 as cathode in aqueous Mg-Li batteries with excellent capacity

Abstract

Aqueous batteries are appealing for large-scale storage applications, due to their high safety level, low cost, and excellent durability. In this study, we reported a new anode material, namely sulfur perylene-3,4,9,10-tetracarboxylate (PTC-S), which is more stable than other electrode materials used in aqueous Mg-Li ion batteries. When PTC-S is used as the anode in 0.5 M MgCl2 + 0.5 M LiCl with a current density of 50 mA g−1, the discharge specific capacity is 287.3 mAh g−1 at the initial cycle and the capacity retention rate is still close to 100% at over 1000 cycles. The monomer structural material conjugated with bifunctional groups can provide the space for the intercalation of Mg2+ and Li+ at the same time, shorten the ion transmission path and accelerate the transmission speed of metal ions in the electrode. In order to develop aqueous battery as quickly as possible, LiMn2O4 and PTC-S are used as cathode and anode materials, respectively, in a dual-ion salt aqueous battery. The PTC-S‖LiMn2O4 battery exhibits a high capacity and an excellent cycling stability performance in aqueous Mg-Li ion battery. The battery has a high capacity performance of 240.0 mAh g−1 at a voltage ranging from 0.0 V to 1.8 V, as well as a high specific energy density of 172.8 Wh kg−1 and remarkable cycling stability. PTC-S in 0.5 M MgCl2 electrolyte has a current density of 100 mA g−1, a specific discharge capacity of 203 mAh g−1 and a first-cycle Coulomb efficiency close to 100%. Under the same test conditions, the discharge specific capacity is higher than that of the perylene-3,4,9,10-tetracarboxylic dihydride (PTCI) electrode (101 mAh g−1), and the capacity retention rate is increased by 30.4%.