Technical Field
The present disclosure relates to a composition for use for a positive electrode of a non-aqueous secondary battery, such as lithium-ion secondary battery, and a method of producing the same.
Description of Related Art
Non-aqueous secondary batteries, such as lithium-ion secondary batteries, are widely used as a power source of small devices such as mobile phones and notebook computers. Since a non-aqueous secondary battery can be operated at a higher average operating voltage, the use of non-aqueous secondary batteries as a source of electricity for driving large devices such as electric vehicles is now being studied.
For the positive electrode of a non-aqueous secondary battery, a lithium transition metal complex oxide, such as a lithium cobalt complex oxide, is usually used as an active material. A lithium transition metal complex oxide containing nickel as a transition metal (lithium nickel complex oxide) has a capacity per unit mass even larger than that of a lithium cobalt complex oxide. Thus, the use of a lithium nickel complex oxide as a positive electrode active material for a non-aqueous secondary battery for use as a source of electricity for driving large devices is expected.
There is also an example of a positive electrode composition obtained by mixing titanium boride with a positive electrode active material.
JP 2012-048838 A describes an example where a positive electrode active material composed of lithium transition metal complex oxide particles represented by the compositional formula Li1.1Ni0.3Co0.4Mn0.3O2 is mixed with TiB2 particles having an average particle diameter of 2 μm so that the resultant mixture have a molar ratio of 99:1. The document also describes an example where the resultant mixture is calcined to sinter TiB2 particles on the surfaces of the lithium transition metal complex oxide particles.
JP H08-222219 A describes an example where 5 wt % of TiB2 particles are fused on the surface of a positive electrode active material composed of a lithium nickel complex oxide. The fusion is said to have been achieved by applying mechanical energy to TiB2 particles. The average particle diameter, the particle size, and the like of the TiB2 particles are unclear.