High-compaction-density positive electrode material and electrochemical energy storage device

Abstract

The invention relates to the technical field of batteries. The invention relates to a cathode material, in particular to a high-compaction-density cathode material and an electrochemical energy storage device. The positive electrode material comprises a lithium-nickel transition metal oxide A and a lithium-nickel transition metal oxide B. The lithium-nickel transition metal oxide A is secondary particles, and the chemical formula of the lithium-nickel transition metal oxide A is shown as a formula I: Lia1(Nib1Coc1Mnd1)x1M1-x1O2-e1Xe1, the lithium-nickel transition metal oxide B is of a singlecrystal structure or a single crystal-like structure, and the chemical formula of the lithium-nickel transition metal oxide B is shown as a formula II: Lia2(Nib2Coc2Mnd2)x2M'1-x2O2-e2X'e2 (II), and the grain size D104 of the positive electrode material and the particle size distribution change rate [delta] PSD of the positive electrode material meet the condition that D104 * [delta]PSD is more than or equal to 50 nm and less than or equal to 600 nm. The positive electrode material comprises the large-particle lithium-nickel transition metal oxide A and the small-particle lithium-nickel transition metal oxide B, so that the energy density of the battery is improved; by regulating and controlling the crystallinity and particle size distribution of the mixed positive electrode material, the problem of particle breakage of high-nickel powder in the cold pressing and circulating process is solved, the powder compaction density of the high-nickel active material is improved, and it is guaranteed that the gas production rate is low and the circulating performance is excellent.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a high compacted density positive electrode material and an electrochemical energy storage device. Background technique [0002] In order to pursue high energy density, cathode materials are generally optimized from two aspects. On the one hand, the nickel content of the positive electrode material is increased to increase its reversible gram capacity; on the other hand, the powder compaction density is increased through the combination of large and small particles. At present, high-nickel ternary materials have high reversible gram capacity, but do not have high powder compaction density. [0003] At present, there are two common schemes for high powder compaction density. One is large-grain polycrystals mixed with small-grain polycrystals. This method is usually used in low-nickel ternary materials, and its gram capacity is low, resulting in low energy density of the posit...

AI Technical Summary

Problems solved by technology

This method is usually used in low-nickel ternary materials, and its gram capacity is low, resulting in low energy density of positive electrode materials

A small number of high-nickel polycrystals with large particles mixed with high-nickel polycrystals with small particles have a high energy density, but the small-grain high-nickel polycrystals are easily broken during the cold pressing process, resulting in serious gas production.

Another solution is a high-nickel polycrystalline material with a wider particle distribution, but too wide a particle distribution is also easily broken during cold pressing and circulation, resulting in the same gas production problem

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