Lithium-rich or Ni-rich layered oxides cathode materials have attracted great attentions owing to their specific high capacity for lithium-ion batteries, but the poor rate capability and voltage fade of lithium-rich layered oxide cathode materials limited their practical applications. Element doping, coating and vacancy engineering are effective strategies to improve the electrochemical performances of Li-rich or Ni-rich layered oxides cathode materials. The degree of Li/Ni mixing not only affects the rate capability but also the structure stability and the cycling stability. We plan to use neutron diffraction to analyze the occupancy of Li, Ni and O, the degree of Li/Ni mixing, the interlayer spacing and TM-O/Li-O bond length and oxygen vacancy to understand the structure-property relationship and offers some insights into designing high performance cathode materials for Li-ion batteries.