Doped Layered Cathode Particles With Oxide Coating for Heat Stability
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Solution Overview
Problem
Lithium-ion secondary batteries face challenges in achieving high energy density while maintaining good high-temperature cycling and storage performance due to the poor performance of traditional positive electrode active materials at elevated temperatures.
Innovation Solution
A positive electrode active material is developed, comprising secondary particles with a lithium transition metal oxide and a coating layer of oxide M2, where element M1 is uniformly doped in the transition metal site and element M2 is applied as a coating, optimizing the chemical formula and structural properties to enhance stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel-containing lithium transition metal oxide is used as positive electrode active material to increase specific capacity, then energy density is improved, but high-temperature cycling performance deteriorates
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core contains nickel-rich lithium transition metal oxide for high capacity, while the shell contains aluminum-rich lithium transition metal oxide specifically at the surface to provide thermal stability and protect against degradation during high-temperature cycling. This spatial differentiation of material properties resolves the contradiction between high capacity and high-temperature stability.
Solution Approach 2:
The patent uses composite materials by combining nickel-containing lithium transition metal oxide with aluminum-containing lithium transition metal oxide in a core-shell configuration. The nickel-rich core provides high specific capacity while the aluminum-rich shell provides thermal stability and structural integrity at elevated temperatures, thereby achieving both high energy density and good high-temperature cycling performance.
2Quantity of substance
If nickel-containing lithium transition metal oxide is used to increase specific capacity, then energy density is improved, but high-temperature storage performance deteriorates
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core contains nickel-rich lithium transition metal oxide for high capacity, while the shell contains aluminum-rich lithium transition metal oxide specifically at the surface to provide thermal stability and protect against degradation during high-temperature cycling. This spatial differentiation of material properties resolves the contradiction between high capacity and high-temperature stability.
Solution Approach 2:
The patent uses composite materials by combining nickel-containing lithium transition metal oxide with aluminum-containing lithium transition metal oxide in a core-shell configuration. The nickel-rich core provides high specific capacity while the aluminum-rich shell provides thermal stability and structural integrity at elevated temperatures, thereby achieving both high energy density and good high-temperature cycling performance.
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 solution significantly improves the energy density, high-temperature storage performance, and high-temperature cycling performance of lithium-ion secondary batteries by increasing specific capacity, mechanical strength, and reducing side reactions, leading to a more stable and efficient battery operation.
Implementation Method 1
element M1 is uniformly doped in the transition metal site
Implementation Method 2
a coating layer of oxide M2, where element M2 is applied as a coating
Data Source
AI summary
This application discloses a positive electrode active material, including secondary particles and a coating layer applied on an exterior surface of each of the secondary particles, where the secondary particle includes a lithium transition metal oxide that contains a doping element M1, the coating layer includes an oxide of element M2, M1 is selected from one or more of Si, Ti, Cr, Mo, V, Ge, Se, Zr, Nb, Ru, Rh, Pd, Sb, Te, Ce, and W, and M2 is selected from one or more of Mg, Al, Ca, Ce, Ti, Zr, Zn, Y, and B; a relative deviation of local mass concentration of element M1 in the secondary particle is less than 20%; and the secondary particle from the core to the exterior surface of the particle includes a plurality of layers of primary particles arranged along radial direction of the secondary particle.