Improving cycle stability of Ni-rich LiNi0.8Mn0.1Co0.1O2 cathode materials by Li4Ti5O12 coating

The surface of LiNi0.8Mn0.1Co0.1O2 (NCM811) cathode is coated with Li4Ti5O12 with a thickness of 10-12 nm by the solvent evaporated calcination method to generate T2-NCM811 cathode, which significantly reduces the particle cracking. The cyclic stability of the T2-NCM811 cathode is greatly improved by particle-stabilized structure. After 500 cycles between 2.8 and 4.3 V, its capacity retention rate is 83%, which is higher than that of NCM811 (67%). This cyclic stability is attributed to the inhibition of secondary crystal cracking by the coating, which the structure of the particles is kept stable in a long period and protects the internal particles from harmful electrolytes. The discharge capacity of NCM811 cathode at 10C is 92.6 mAh g(-1), while that for T2-NCM811 cathode raises to 111.5 mAh g(-1). This is because a certain amount of Ti3+/Ti4+ doping to the surface of NCM811 reduces Li/Ni mixing and increases the lattice parameters on the surface of material; this helps to accelerate the electronic conductivity and enhance the transport of Li+.

Automated summary

The application of Li4Ti5O12 coating on the NCM811 cathode to form the T2-NCM811 cathode can significantly reduce particle cracking and improve cyclic stability. Additionally, the coating inhibits secondary crystal cracking, protects internal particles, and enhances the electrode performance.