A Mn 3 O 4 nanospheres@rGO architecture with capacitive effects on high potassium storage capability.

A two dimensional (2D) Mn 3 O 4 @rGO architecture has been investigated as an anode material for potassium-ion secondary batteries. Herein, we report the synthesis of a Mn 3 O 4 @rGO nanocomposite and its potassium storage properties. The strong synergistic interaction between high surface area reduced graphene oxide (rGO) sheets and Mn 3 O 4 nanospheres not only enhances the potassium storage capacity but also improves the reaction kinetics by offering an increased electrode/electrolyte contact area and consequently reduces the ion/electron transport resistance. Spherical Mn 3 O 4 nanospheres with a size of 30-60 nm anchored on the surface of rGO sheets deliver a high potassium storage capacity of 802 mA h g -1 at a current density of 0.1 A g -1 along with superior rate capability even at 10 A g -1 (delivers 95 mA h g -1 ) and cycling stability. A reversible potassium storage capacity of 635 mA h g -1 is retained (90%) after 500 cycles even at a high current density of 0.5 A g -1 . Moreover, the spherical Mn 3 O 4 @rGO architecture not only offers facile potassium ion diffusion into the bulk but also contributes surface K + ion storage. The obtained results demonstrate that the 2D spherical Mn 3 O 4 @rGO nanocomposite is a promising anode architecture for high performance KIBs.