Micro-scale core-shell structured Li[(Ni 1/3 Co 1/3 Mn 1/3 ) 0.8 (Ni 1/2 Mn 1/2 ) 0.2 ]O 2 powders for use as cathode material are synthesized by a co-precipitation method. To protect the core material Li[Ni 1/3 Co 1/3 Mn 1/3 ]O 2 from structural instability at high voltage, a Li[Ni 1/2 Mn 1/2 ]O 2 shell, which provides structural and thermal stability, is used to encapsulate the core. A mixture of the prepared core-shell precursor and lithium hydroxide is calcined at 770°C for 12h in air. X-ray diffraction studies reveal that the prepared material has a typical layered structure with an R3¯m space group. Spherical morphologies with mono-dispersed powders are observed in the cross-sectional images obtained by scanning electron microscopy. The core-shell Li[(Ni 1/3 Co 1/3 Mn 1/3 ) 0.8 (Ni 1/2 Mn 1/2 ) 0.2 ]O 2 electrode has an excellent capacity retention at 30°C, maintaining 99% of its initial discharge capacity after 100 cycles in the voltage range of 3–4.5V. Furthermore, the thermal stability of the core-shell material in the highly delithiated state is improved compared to that of the core material. The resulting exothermic onset temperature appear at approximately 272°C, which is higher than that of the highly delithiated Li[Ni 1/3 Co 1/3 Mn 1/3 ]O 2 (261°C).