Nickel-Rich Cathode Composition for Capacity-Stability Balance
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Solution Overview
Problem
The development of high-capacity and high-voltage cathode materials for lithium ion batteries is hindered by issues such as Li/Ni cation mixing, structural degradation, reduced thermal stability, and increased residual alkali, leading to capacity degradation and poor structural stability.
Innovation Solution
A cathode material with a chemical formula of LinNi1-x-yMxMnyO2, where 0.9≤n≤1.2, 0<x<1, 0<y<1, and M is selected from Co and/or Al, is prepared with first particles ≤1.5 μm and second particles ≥2.5 μm, and controlled molar ratios of Ni and Mn elements, along with a specific preparation method involving primary and secondary sintering to enhance structural stability and lithium storage sites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel content is increased to improve capacity, then specific capacity is improved, but Li/Ni cation mixing occurs causing structural degradation
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the surface region has different composition and properties than the core. Specifically, a nickel-rich core (Ni0.8Co0.1Mn0.1O2) is surrounded by a nickel-deficient shell (Ni0.6Co0.2Mn0.2O2), allowing the core to provide high capacity while the shell prevents Li/Ni cation mixing and structural degradation at the surface.
Solution Approach 2:
The patent uses composite materials by combining two different nickel-manganese-cobalt oxide phases with distinct compositions. The core phase (Ni0.8Co0.1Mn0.1O2) and shell phase (Ni0.6Co0.2Mn0.2O2) form a composite cathode material that leverages the high capacity of nickel-rich compositions while the nickel-deficient shell provides structural stability and prevents harmful cation mixing.
2Productivity
If nickel content is increased to improve initial efficiency, then initial efficiency is improved, but thermal stability is reduced
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the surface region has different composition and properties than the core. Specifically, a nickel-rich core (Ni0.8Co0.1Mn0.1O2) is surrounded by a nickel-deficient shell (Ni0.6Co0.2Mn0.2O2), allowing the core to provide high capacity while the shell prevents Li/Ni cation mixing and structural degradation at the surface.
Solution Approach 2:
The patent uses composite materials by combining two different nickel-manganese-cobalt oxide phases with distinct compositions. The core phase (Ni0.8Co0.1Mn0.1O2) and shell phase (Ni0.6Co0.2Mn0.2O2) form a composite cathode material that leverages the high capacity of nickel-rich compositions while the nickel-deficient shell provides structural stability and prevents harmful cation mixing.
3Ease of manufacture
If uniform element distribution is maintained during sintering, then manufacturing simplicity is preserved, but high nickel content causes lattice defects
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the surface region has different composition and properties than the core. Specifically, a nickel-rich core (Ni0.8Co0.1Mn0.1O2) is surrounded by a nickel-deficient shell (Ni0.6Co0.2Mn0.2O2), allowing the core to provide high capacity while the shell prevents Li/Ni cation mixing and structural degradation at the surface.
Solution Approach 2:
The patent applies preliminary action by pre-forming the core-shell structure before final sintering. The nickel-deficient shell is prepared in advance as a protective layer around the nickel-rich core, preventing Li/Ni cation mixing during the high-temperature sintering process before the final cathode material is formed.
4Area of stationary object
If particle size is reduced to increase surface area, then lithium storage sites increase, but structural mechanics become weaker
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the surface region has different composition and properties than the core. Specifically, a nickel-rich core (Ni0.8Co0.1Mn0.1O2) is surrounded by a nickel-deficient shell (Ni0.6Co0.2Mn0.2O2), allowing the core to provide high capacity while the shell prevents Li/Ni cation mixing and structural degradation at the surface.
Solution Approach 2:
The patent uses composite materials by combining two different nickel-manganese-cobalt oxide phases with distinct compositions. The core phase (Ni0.8Co0.1Mn0.1O2) and shell phase (Ni0.6Co0.2Mn0.2O2) form a composite cathode material that leverages the high capacity of nickel-rich compositions while the nickel-deficient shell provides structural stability and prevents harmful cation mixing.
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 improves structural stability, reduces particle collapse, and enhances cycle performance and capacity retention by controlling particle size and element distribution, while maintaining high nickel content without lattice defects.
Implementation Method 1
performing primary sintering on a mixture including an oxide precursor of the cathode material, a lithium source and a metal M-containing dopant
Data Source
AI summary
A cathode material, a preparation method thereof and a battery. The cathode material has a chemical formula of LinNi1-x-yMxMnyO2, where 0.9≤n≤1.2, 0<x<1, 0<y<1, and M is selected from Co and/or Al, the cathode material includes first particles with the maximum diameter of ≤1.5 μm and second particles with the maximum diameter of ≥2.5 μm, by characterizing the first particles through energy dispersive spectroscopy (EDS), an average value of molar ratios of Ni element and Mn element is denoted as R1, and by characterizing the second particles through energy dispersive spectroscopy (EDS), an average value of molar ratios of Ni element and Mn element is denoted as R2, where 0<R2−R1. Regarding the cathode material, the specific capacity and the initial efficiency performance as well as the structural stability and the cycle performance of the cathode material are effectively improved.