Utilizing Oxygen-Vacancy-Rich Violet Tungsten Oxide Enabling Ultralong Cycling of Nickel-Rich Cathodes at High Voltage

Nickel-rich cathodes have become widely used recently but tend to become unstable under high voltage, resulting in metal atom rearrangement and oxygen lattice distortions. During high-voltage charging, nickel oxidation weakens oxygen-transition metal bonds, causing oxygen release and increasing risks like thermal runaway. To address these stability issues, we developed an oxygen vacancy-rich WO 2.72 coating that promotes oxygen vacancy formation on the particle surface, regulating lattice oxygen release within the bulk phase. Additionally, we conducted a detailed analysis of the inhibition mechanism of lattice oxygen release in electrochemical processes, using methods like EPR, DEMS, XPS, and RIXS. Due to its effective inhibition of oxygen release and enhanced particle mechanical properties, the coating achieved an 80.3% retention rate after 600 cycles at 4.5 V, highlighting its potential for stabilizing nickel-rich cathodes in lithium-ion batteries. This method can also be directly applied to designing other high-energy cathode materials facing stability and capacity challenges.