Positive electrode active material, positive electrode, battery, and electric device

The invention provides a positive electrode active material, which comprises lithium manganese iron phosphate particles, a phosphate solid electrolyte layer coating the lithium manganese iron phosphate particles, and a carbon layer coating the phosphate solid electrolyte layer, and the coating rate of the phosphate solid electrolyte layer is less than 100%. The positive electrode active material has excellent rate capability and low-temperature performance, and is beneficial to use. The invention also provides a positive electrode, a battery and electric equipment. 本申请提供了一种正极活性材料，包括磷酸锰铁锂颗粒、包覆所述磷酸锰铁锂颗粒的磷酸盐固态电解质层，以及包覆所述磷酸盐固态电解质层的碳层，所述磷酸盐固态电解质层的包覆率小于100％。该正极活性材料的倍率性能和低温性能优异，有利于其使用。本申请还提供了正极、电池和用电设备。