The effect on electrochemical properties of Ti4+ and V5+ doping in LiNi0.8Co0.1Mn0.1O2

In this work, Ti ⁴⁺and V ⁵⁺ are doped into NCM811 to improve the electrochemical properties. The capacity retention of bimetal-doped material is 66.7 % after 500 cycles (1 C=200 mAh·g ⁻¹ ), exhibiting the 30 % improvement compared with original NCM811. The rate performance is improved from 53.4 % to 58 % at 5 C. XRD results shows the lattice parameters are increased after doping Ti ⁴⁺ and V ⁵⁺ . The analysis of cyclic voltammetry shows Ti ⁴⁺ and V ⁵⁺ doping can improve the diffusion rate of lithium ions. The dQ/dV curves indicate that Ti ⁴⁺ and V ⁵⁺ doping can improve the reversibility of the H2⇋H3 phase, stabilizing the structure of the material. The FIB-SEM shows the sintered primary particles become elongated and arranged in a radioactive manner after Ti ⁴⁺ and V ⁵⁺ doping, which can alleviate the accumulation of local stresses and reduce the micro-cracks created during material cycling. In summary, Ti ⁴⁺ and V ⁵⁺ co-doping can improve the electrochemical performance of LiNi _0.8Co _0.1Mn _0.1O ₂.