Facile synthesis of K0.5Mn2O4·1.5H2O/rGO composites with ultrahigh zinc storage properties

Zinc-ion batteries have drawn much attention due to their good safety and low cost. In this work, a straightforward 1-pot pyrolysis process has been utilized to prepare novel K_0.5Mn₂O₄·1.5H₂O/rGO (KMrGO) composites. In KMrGO, the layered structure of reduced graphene oxide (rGO) can efficiently improve the electrical conductivity of K_0.5Mn₂O₄·1.5H₂O, enabling KMrGO to demonstrate high zinc storage performance. Although a very small amount of rGO (∼1.8%) has been introduced, the reversible capacity of KMrGO reaches 230.1 mAh g⁻¹ after 250 cycles at 0.2 A g⁻¹. Even after 1200 cycles at a high current density of 1 A g⁻¹, KMrGO remains a good capacity retention of 70.2%. Considering the simple preparation of KMrGO, this method can provide a new route for synthesizing other metal dioxide/rGO composites.