LiNiMnCoO2 Cathode with Coated Particles for High Capacity
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Solution Overview
Problem
Current positive electroactive materials for lithium-ion batteries, such as lithium nickel cobalt aluminum oxide, lithium iron phosphate, and lithium manganese oxide, face limitations in capacity, rate performance, and safety for electric vehicle applications, failing to meet the demands of the emerging market.
Innovation Solution
Development of a lithium nickel manganese cobalt oxide compound with a higher tap density and specific particle size distribution, characterized by a Span range of 1.04 to 1.68, and a composition of Lithium (Li), Nickel (Ni), Manganese (Mn), and Cobalt (Co), which can be formed into closely packed particles with a well-defined spherical structure, enhancing energy density and discharge rate capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium nickel cobalt aluminum oxide is used to deliver high capacity, then energy density is improved, but safety deteriorates with significant safety problems
Solution Approach 1:
The patent uses a composite material system consisting of Li-rich layered oxide particles (providing high capacity) combined with coated particles (providing safety and stability). This composite structure allows the high-capacity Li-rich material to be protected by the coating layer, resolving the contradiction between achieving high capacity and maintaining safety.
2Reliability
If lithium iron phosphate is used to improve safety and cycle life, then reliability is improved, but energy density deteriorates with the lowest energy density
Solution Approach 1:
The patent creates a composite where Li-rich layered oxide particles (high energy density) are combined with coated particles (safety and stability). The Li-rich material provides the necessary energy density while the coating structure maintains safety, avoiding the low energy density limitation of pure lithium iron phosphate.
3Reliability
If lithium manganese oxide is used to improve thermal stability, then safety is improved, but capacity deteriorates with relatively low capacity
Solution Approach 1:
The patent combines Li-rich layered oxide particles (high capacity) with coated particles (thermal stability). The Li-rich material provides the necessary capacity while the coating structure delivers thermal stability, overcoming the low capacity limitation of pure lithium manganese oxide.
4Quantity of substance
If lithium nickel manganese cobalt oxide is used to increase capacity, then energy density is improved, but rate performance deteriorates
Solution Approach 1:
The patent segments the positive electrode material into two distinct particle types: Li-rich layered oxide particles (providing capacity) and coated particles (providing rate performance). This segmentation allows each particle type to optimize for its specific function, resolving the contradiction between high capacity and good rate performance.
Data Source
AI summary
A positive electroactive material for a lithium-ion battery can have a tap density ranging from 2.50 to 2.90 g/cm3, a Span value ranging from 1.04 to 1.68 and/or a capacity ranging from 195 to 210 mAh/g obtained using a discharging current of C/5 current rate. The material can have a formula Lia[NixMnyCo1−x−y]zM1−zO2, wherein a is between approximately 1.02 and 1.07, x is between approximately 0.60 to 0.82, y is between approximately 0.09 to 0.20, z is between approximately 0.95 to 1.0, and 1−x−y is greater than 0. A cost-effective and large-scale synthetic method for preparing the positive electroactive material, an electrochemical cell containing the positive electroactive material, and a battery comprising one or more lithium ion electrochemical cells are also described.