POSITIVE ELECTRODE PLATE, PREPARATION METHOD THEREOF, SECONDARY BATTERY, AND ELECTRIC APPARATUS

A positive electrode plate, a preparation method thereof, a secondary battery, and an electric apparatus. The positive electrode plate includes a current collector and a positive electrode film layer formed on at least one side of the current collector. The positive electrode film layer includes a positive electrode active material comprising a substrate and a carbon coating layer on the surface of the substrate. The substrate has a general formula LizFexMn(1-x-y)MyPO4, where 1≤z≤1.1, 0.5≤x≤1, 0≤y≤0.1, and M is at least one of Ti, V, and Mg. At least part of the active material includes primary particles, with no more than 10% having sizes between 80 nm and 180 nm, and no more than 15 particles exceeding 1500 nm within a defined microscopic region. This structure improves the particle size distribution concentration, enhancing the cycling performance of batteries.