High-voltage spinel LiNi0.5Mn1.5O4 is considered the most promising cathode materials for large-scale lithium-ion batteries to meet the fast increasing high energy and power density requirements. However, its commercial applications are restricted due to rigorous capacity fading, particularly at high temperatures. Herein, we propose novel highly uniform nano/submicro LiNi0.5Mn1.5O4 cubes for the first time using cubic MnCO3 precursors, which are prepared via a facile co-precipitation route. The as-synthesized LiNi0.5Mn1.5O4 demonstrates excellent cycle stability and superior rate capability. Specifically, the materials retain a nearly 100% capacity retention after 100 cycles at 25°C. Moreover, under the elevated temperature of 55°C, it can deliver a discharge capacity of 131.7mAhg−1 with the specific energy of 605.1WhKg−1 and even over 98.4% of primal discharge capacity can be maintained for up to 100 cycles.