POSITIVE ELECTRODE ACTIVE MATERIAL FOR ALL-SOLID-STATE LITHIUM ION BATTERIES, POSITIVE ELECTRODE FOR ALL-SOLID-STATE LITHIUM ION BATTERIES, ALL-SOLID-STATE LITHIUM ION BATTERY, AND METHOD FOR PRODUCING POSITIVE ELECTRODE ACTIVE MATERIAL FOR ALL-SOLID-STATE LITHIUM ION BATTERIES

摘要

The present invention provides a positive electrode active material for all-solid-state lithium ion batteries, said positive electrode active material improving the electrode density of a positive electrode and enabling the achievement of excellent volumetric energy density and excellent output characteristics if used in an all-solid-state lithium ion battery. A positive electrode active material for all-solid-state lithium ion batteries, said positive electrode active material being obtained by mixing a positive electrode active material (1) and a positive electrode active material (2). With respect to the positive electrode active material (1), the composition formula thereof is expressed by Li_aNi_bCo_cMn_dAl_eO₂ (wherein 1.00 ≤ a ≤ 1.02, 0.8 ≤ b ≤ 0.9, 0 < c ≤ 0.2, 0 < d ≤ 0.2, (b + c + d) = 1, and 0.02 ≤ e ≤ 0.15); in a cross-section of a particle, the Al concentration C_c in the center of the particle and the Al concentration C_s at a position where the depth from the particle surface is 10 nm satisfy C_s/C_c = 2-10; the intraparticle void fraction is less than 30%; and the average particle diameter (D50) is from 6 μm to 15 μm. With respect to the positive electrode active material (2), the average particle diameter (D50) is from 1 μm to 5 μm.