Single-crystalline LiNi0.5Co0.2Mn0.3O2 (denoted as SC-523) with micron size had been successfully synthesized through a facile method. Electrochemical impedance spectroscopy and differential scanning calorimetry were carried out to identify the improved electrochemical performance and desired thermal stability. Even after 100 cycles, SC-523 still delivered a discharge capacity of 151.1 mA h g(-1) (capacity retention with 90.3%) at 1 C in voltage range from 3.0 to 4.5 V (vs. Li/Li+), while polycrystalline spherical LiNi0.5Co0.2Mn0.3O2 (denoted as PC-523) only exhibited 141.7 mA h g(-1) (capacity retention with 78.4%). Besides, SC-523 shows a higher decomposition temperature of 332.13 degrees C, 14.61 degrees C higher than that of PC-523 during the thermal decomposition. Consequently, single-crystalline particles with robust morphological integrity ensure the enhanced cycling stability and thermal stability.