A tailored high-nickel cobalt-free Na-doped LiNi_0.9Mn_0.06Al_0.04O₂ cathode for superior lithium storage

To meet the growing demands of the electric vehicle market, it is urgent to search for high-nickel cobalt-free layered cathodes for lithium-ion batteries (LIBs) to boost electrochemical energy storage. However, their practical application is severely limited by some disadvantages in terms of relatively high cost, inherent structural instability and severely detrimental phase transitions. Herein, an Na-doped LiNi_0.9Mn_0.06Al_0.04O₂ sample was fabricated by a simple high-temperature solid-state method. When evaluated as a cathode for LIBs, it delivers prospective electrochemical performance with a high capacity of 252.98 mA h g^-1 at 0.1C and excellent cycling stability of 86.7% after 100 cycles at 0.5C. The significant improvement of electrochemical performance is primarily attributed to the broadened Li interlayer spacing and stabilized crystal structure by introducing sodium ions. The present work may demonstrate great potential in high-performance electrode materials by an Na-doped strategy.