Crystal form modulation enables high-performance manganese dioxide cathode for aqueous zinc ion battery.

Manganese dioxide (MnO 2) is a promising cathode candidate for advanced rechargeable Zn-ion batteries (ZIBs) owing to its low cost, high theoretical capacity and high output voltage. However, the poor stability and low practical capacity has greatly hampered its commercialization. Herein, we demonstrate a crystal form modulation strategy to enhance the capacity and cycling durability of commercial γ-MnO 2 as robust ZIBs cathode material. By introducing new β-MnO 2 crystal form with compact (1 × 1) tunnel structure after simple calcination, the γ- and β- co-existed MnO 2 (denoted as m -MO) shows enhanced electrical conductivity and structural stability. Consequently, the m -MO cathode exhibits an excellent capacity of 273.6 mAh g–1 at 0.25 A g–1 with good cycle stability, much higher than the pristine γ-MnO 2 cathode (156.7 mAh g–1). Furthermore, an aqueous ZIBs based on m -MO cathode delivers a large peak energy density of 349.1 W h kg–1 at 0.322 kW kg–1 and power density of 4.77 kW kg–1 at 123.01 W h kg–1. This work presents an effective crystal form modulation strategy to construct high-performance ZIBs cathodes based on commercial MnO 2 , which is highly potential for further commercial applications. [Display omitted] • A new kind of γ- and β- co-existed MnO 2 (m -MO) is developed from commercial γ-MnO 2 via crystal form modulation strategy. • The introduction of β-MnO 2 enables m -MO electrode with enhanced capacity and reaction kinetics. • An aqueous rechargeable Zn// m -MO battery with high capacity (273.6 mAh g–1 at 0.25 A g–1) is constructed. [ABSTRACT FROM AUTHOR]