Divalent Ion Pillaring and Coating on Lithium Cobalt Oxide Cathode for Fast Intercalation of Li+ Ion with High Capacity

Abstract

The development of high‐performance lithium‐ion batteries (LIBs) is essential for sustainable energy storage and utilization. Lithium cobalt oxide (LiCoO2, LCO) is widely used as a cathode material in LIBs due to its excellent electrochemical properties. However, its capacity is limited by structural changes and severe side reactions at high voltage and temperature. To overcome this issue, this study combines two strategies to enhance the intercalation kinetics of the LCO cathode. First, ionic pillars of various ions (e.g., Mg2+ and Ca2+) are doped to stabilize the structure at high voltage. Second, lithium‐ion conducting lithium phosphate (Li3PO4) is coated to prevent direct contact between the liquid electrolytes and LCO particles, minimizing the formation of resistive surface films. The combination of these strategies results in a synergetic effect that significantly improves the energy density, thermal stability, cycling stability, and rate capability of the cathode. A rate capability of 100 mAh g−1 at 10C is achieved, and a stable cycle performance with 98% capacity retention after 100 cycles at 0.5C is observed. Herein, the potential pathways of enhancing the energy density of current cathode materials through a synergistic combination of surface and structural engineering are highlighted.