Enhancing high-voltage performances of nickel-based cathode material via aluminum and progressive concentration gradient modification

Increasing the average Ni content and extending the working voltage are effective approaches to enhancing the reversible capacity of Li[Ni1−x−yCoxMny]O2 layered oxide cathode materials. However, these would cause severe structural instability and rapid capacity fade upon cycling. In order to address this issue, Al3+ modified novel progressive concentration gradient material Li[Ni0.7Co0.13Mn0.17]O2 is successfully prepared, which maximizes the average Ni content as well as the surficial and structural stability at high cut-off voltage of 4.5 V, attributing to the progressively accelerated transition metals evolution rates from core to surface of the spherical particles and the Al3+ suppressed high-voltage phase transition. Consequently, superior reversible capacity of 206.1 mA h g−1 at 0.1C and capacity retention of 95.7% after 50 cycles at 0.5C rate are obtained, providing skilful approach to obtain promising high-performance cathode materials with both high energy density and long calendar life to satisfy the growing demands of future electric vehicles.