A novel low-cobalt long-life LiNi0.88Co0.06Mn0.03Al0.03O2 cathode material for lithium ion batteries

Abstract

Compared to the fossil-fuelled cars, developing a high-safety, low-cost, long-life lithium ion battery with higher energy density is critical important to enhance the market acceptance of electric vehicles. Herein, a novel quaternary low-cobalt LiNi0.88Co0.06Mn0.03Al0.03O2 cathode material (NCMA-ZB) is rationally designed and synthesized by a two-step modification of Zr-doping and LiBO2-coating for the first time. Impressively, the two-step modified NCMA-ZB cathode exhibits greatly improved long-term cycling performance, voltage fading, high-temperature performance and safety performance. Further studies demonstrate that the two-step modification of Zr-doping and LiBO2-coating can remarkably strengthen the structural stability during the cell cycling. In addition, the thermal decomposition temperature of the modified NCMA-ZB cathode is increased by ∼8 ℃. Finally, the coin cells assembled by the as-prepared NCMA-ZB cathodes show a discharge specific capacity of 211.7 mAh g−1 and an initial coulombic efficiency of 89.0% at 0.1 C and 25 ℃ with a cut-off voltage range of 3.0–4.3 V. The corresponding capacity retention reaches 98.1% after 50 cycles at 1C. It additionally provides significantly improved high-temperature electrochemical performance of capacity retention of 97.8% after 50 cycles at 45 ℃. Moreover, the 18650-type cylindrical full cell configured with NCMA-ZB as the cathode obtains capacity retention of 95.8% after 1000 cycles at 1 C at 2.75–4.2 V.