Preparation method of high-performance cobalt-free lithium-rich positive electrode material

The invention provides a method for improving the battery capacity performance and the cycling stability of a cobalt-free lithium-rich positive electrode material by using nano aluminum oxide as a binder of the cobalt-free lithium-rich positive electrode material. The method mainly comprises the following steps: weighing a certain molar weight of a Ni source and a Mn source, dissolving the Ni source and the Mn source in a mixed solution of deionized water and absolute ethyl alcohol, carrying out ultrasonic treatment until the solution is clear and transparent, and marking the solution as a solution A; dissolving a carbonate complexing agent with a certain stoichiometric ratio into deionized water, and marking as a solution B; pouring the solution A into a hydrothermal reaction kettle, rapidly pouring the solution B into the hydrothermal reaction kettle, and heating to carry out hydrothermal reaction; washing, suction filtration and drying treatment are carried out on the precursor obtained through the hydroth