P2-type Na0.65Mn0.6Ni0.35Cu0.05O2 microspheres assembled irregularly with massive primary nanoparticles are prepared via hydrothermal method and subsequent two-step calcination process. As expected, the P2-type Na0.65Mn0.6Ni0.35Cu0.05O2 microspheres show superior electrochemical performance in terms of high-rate capability and long-period cycling stability. This material exhibits a reversible capacity of 81 mA h g(-1) and exceptional capacity retention up to 79% over 150 cycles even at the high current density of 1 A g(-1). The distinctive spherical structure with high specific surface area can be accountable to the excellent electrochemical properties, which offers abundant surface sodium storage sites and shortened diffusion paths of sodium ions. Therefore, this work puts forward a feasible method to design nanoparticles assembled microspheres for layered oxides with high-rate performance as a promising cathode material for sodium ion batteries. (C) 2019 The Electrochemical Society.