Nowadays, the development of high-voltage LiCoO₂ (lithium cobalt oxide, LCO) cathodes has attracted the widespread attention from both the academic and industry fields. Among the multiple concerns, researches on the surface issues would provide the most effective performance optimization pathway for the synthesis of high-voltage LCO. In this work, the issues of high-voltage LCO, including the phase transitions and crack formation, the oxygen redox related issues and side reactions, as well as the surface structure degradation, have been systematically reviewed. Then, we further clarify the surface modulations, and the interplay between the surface modulation and electrolyte tuning. Finally, we propose our prospects for developing the more advanced LCO cathodes, including the low-cost and high-quality manufacturing, designing suitable LCO cathodes in some extreme conditions (such as high-temperature, high-rate charging, low temperature, etc.), and achieving stabilized capacity release of about 220 mAh·g^–1 of LCO, etc. We hope that this work can serve as a reference to promote the development and application of high-voltage LCO in future.