Nickel Cobalt Lithium Manganate Cathode With Porous Outer Layer
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Solution Overview
Problem
Existing lithium ion batteries using nickel cobalt manganese hydroxide and nickel cobalt lithium manganate cathode materials suffer from poor rate capability and high-temperature storage performance.
Innovation Solution
A nickel cobalt manganese hydroxide with a core and loose, porous outer layer is prepared through a complex-precipitation and pulse current coprecipitation process, followed by calcination with a lithium source to form a nickel cobalt lithium manganate cathode material, which has a compact interior and loose exterior structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional complex-precipitation method is used to prepare nickel cobalt manganese hydroxide, then the preparation process is simple, but the resulting lithium ion battery has poor rate capability and poor high-temperature storage performance
Solution Approach 1:
The patent combines complex-precipitation method with pulse current coprecipitation method into a hybrid preparation process. The complex-precipitation creates the base nickel cobalt manganese hydroxide structure, while the pulse current coprecipitation adds a porous outer layer, achieving both structural complexity for performance and process integration for efficiency
Solution Approach 2:
The patent introduces a porous outer layer structure in the nickel cobalt manganese hydroxide particles through pulse current coprecipitation. This porous structure increases surface area and facilitates ion transport, directly improving rate capability and high-temperature storage performance of the lithium ion battery
2Use of energy by moving object
If dense nickel cobalt lithium manganate cathode material is prepared, then the energy density is high, but the rate capability is poor
Solution Approach 1:
The patent creates a heterogeneous structure where the inner core maintains high density for energy storage, while the outer layer develops porosity for fast ion transport. This local differentiation of structural properties allows simultaneous optimization of energy density and rate capability
Solution Approach 2:
The cathode material particles are segmented into an inner dense core region and an outer porous layer region. This segmentation allows the core to provide high energy density while the outer layer provides rapid lithium ion diffusion pathways, resolving the contradiction between energy density and rate capability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The resulting lithium ion battery exhibits high energy density and improved rate capability, with energy density of 1.5-2.5 Wh/cm3 and rate capability of 90-99% at 5 C/0.2 C.
Implementation Method 1
simultaneously dripping the water solution A in the step (1), the water solution B in the step (2) and the ammonium hydroxide solution C in the step (3) into a reaction kettle under the conditions of being protected by nitrogen gas, being stirred and being heated to 40-70° C., and after the reaction for a certain time
Implementation Method 2
heating the materials to 600-1100° C. in air or oxygen gas atmosphere, performing continuous calcination for 8-20 h at 600-1100° C.
Data Source
AI summary
The disclosure discloses a nickel cobalt lithium manganate cathode material, a preparation method thereof and a lithium ion battery. The nickel cobalt lithium manganate includes a core and an outer layer covering the outside of the core, the core comprises flaky particles, a D50 particle diameter of the flaky particles in the core is 5-10 μm, and a D50 particle diameter of particles in the outer layer is 0.1-4.5 μm.