Surface-Stabilized LiNiO2 Cathode via ALD Coating
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Solution Overview
Problem
High-capacity LiNiO2 cathode materials face significant capacity degradation and oxygen loss due to unstable surface oxygen atoms, hindering their commercialization despite their high charge capacity potential.
Innovation Solution
A surface-stabilized cathode composition is developed, featuring a core nickel oxide body coated with a thin layer of transition metal or post-transition metal oxide or fluoride, incorporating lanthanide row atoms, applied via atomic layer deposition (ALD) and post-ALD thermal annealing, to prevent surface oxygen evolution and enhance Li ion and electron conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If LiNiO2 is used as cathode material to achieve high charge capacity, then charge capacity is improved, but capacity degradation and oxygen loss occur due to unstable surface oxygen atoms
Solution Approach 1:
The patent applies composite materials by creating a core-shell structure where the core is LiNiO2 cathode material and the shell is a protective coating layer comprising metal oxide or metal fluoride. This composite structure allows the inner LiNiO2 to maintain its high charge capacity while the outer protective layer stabilizes the surface oxygen atoms, preventing capacity degradation and oxygen loss during battery cycling.
Solution Approach 2:
The patent applies local quality by treating only the surface region of the LiNiO2 particles with a protective coating rather than modifying the bulk material. The coating layer is specifically applied to the outer surface where oxygen instability occurs, leaving the high-capacity bulk LiNiO2 structure intact. This localized approach addresses the surface oxygen loss problem while preserving the high charge capacity of the core material.
2Reliability
If surface coating is applied to stabilize LiNiO2, then capacity degradation is reduced, but manufacturing complexity increases due to additional coating steps
Solution Approach 1:
The patent applies parameter changes by optimizing the coating layer thickness to a specific range (1-10 nm) and controlling the concentration of metal atoms (0.1-10 mol%). By precisely controlling these parameters, the coating provides sufficient protection against capacity degradation while minimizing the amount of additional material and processing required, thus balancing performance improvement with manufacturing feasibility.
3Stability of the object's composition
If surface coating layer is applied to prevent oxygen loss, then oxygen stability is improved, but ion and electron conduction may be hindered by the additional layer
Solution Approach 1:
The patent applies porous materials by creating a coating layer with controlled porosity that allows ion and electron transport. The porous structure of the metal oxide or metal fluoride coating provides pathways for Li ion diffusion and electron conduction while still maintaining surface oxygen stability. This porous architecture resolves the contradiction by enabling necessary conduction while preventing oxygen loss.
Solution Approach 2:
The patent applies flexible shells and thin films by using an ultrathin coating layer (1-10 nm) that is thin enough to allow ion and electron conduction but sufficient to stabilize surface oxygen atoms. The thin film structure provides oxygen protection while maintaining good ionic and electronic conductivity, preventing the coating from becoming a barrier to charge transfer.
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 effectively stabilizes the surface phase of LiNiO2, inhibiting capacity degradation and oxygen loss, while maintaining rapid ion and electron transport, thus enhancing the long-term performance and stability of Li-ion batteries.
Implementation Method 1
The surface cathode coating layer contacts and at least partially surrounds an outer surface of the core cathode body... effectively stabilizes the surface phase of LiNiO2, inhibiting capacity degradation and oxygen loss
Implementation Method 2
enhancing the long-term performance and stability of Li-ion batteries... maintaining rapid ion and electron transport
Implementation Method 3
enhancing the long-term performance and stability of Li-ion batteries... maintaining rapid ion and electron transport
Implementation Method 4
forming by atomic layer deposition (ALD), a surface cathode coating layer contacting and at least partially surrounding an outer surface of the core cathode body
Implementation Method 5
applied via atomic layer deposition (ALD) and post-ALD thermal annealing
Data Source
AI summary
Cathode composition including a core cathode body composed of nickel oxide crystallite particles and a surface cathode coating layer contacting and at least partially surrounding an outer surface of the core cathode body. The surface cathode coating layer includes one or more of a transition metal or post-transition metal oxide or fluoride and one or more of lanthanide row atoms having a concentration in a range from about 0.1 to 10 mol %, has a thickness in a range from about 0.5 to 30 nm, and has an amorphous, polycrystalline or composite amorphous/polycrystalline atomic structure. Method of manufacture including preparing a cathode composition includes forming a core cathode body composed of nickel oxide crystallite particles, and, forming by atomic layer deposition, a surface cathode coating layer contacting and at least partially surrounding an outer surface of the core cathode body.