Sub-Nanoscale Cathode Coatings for Stable High-Capacity Li-Ion Batteries
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Solution Overview
Problem
Current lithium-ion batteries face limitations in energy density due to the instability of Ni-rich cathodes and Si anodes, which suffer from surface oxidation, decomposition, and solid-electrolyte interphase formation, leading to shortened lifetimes and hindered commercialization.
Innovation Solution
The use of a ball-mill mechanism integrated with atomic layer deposition (ALD) to achieve uniform and homogeneous coatings on electrode materials, including sub-nanoscale metal oxide coatings and conductive polymer coatings, which enhance surface stability, ionic conductivity, and cyclic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Ni-rich cathodes and Si anodes are used to increase energy density, then specific capacity is improved, but surface stability deteriorates due to oxidation, decomposition, and SEI formation
Solution Approach 1:
A coating layer is introduced as an intermediary between the electrode material surface and the electrolyte. This coating prevents direct contact and harmful reactions while allowing ionic conduction, thus protecting the high-capacity Ni-rich cathode and Si anode from degradation without compromising their electrochemical performance
Solution Approach 2:
The surface properties of the electrode materials are modified by changing the chemical composition and structure through coating. This alters the surface energy, wettability, and chemical reactivity parameters to reduce oxidation and SEI formation while maintaining ionic conductivity
2Manufacturing precision
If conventional ALD technique is used to coat particle surfaces, then coating uniformity is improved, but agglomerated particles cannot be coated conformally
Solution Approach 1:
The ball-milling mechanism introduces dynamic mechanical agitation to the ALD process. This continuous motion breaks up agglomerates and ensures all particle surfaces are exposed to the coating precursors, achieving conformal coating on previously inaccessible surfaces
Solution Approach 2:
Ball-milling applies mechanical energy and vibration to the particle system during coating. This mechanical action disperses agglomerated particles and maintains them in a state where all surfaces can access the vapor-phase precursors, enabling uniform coating coverage
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
This approach enables specific capacities greater than 300 Wh/kg in Li-ion batteries and solid-state Li batteries, improving cycle performance, extending lifetime, and facilitating faster charging and discharging processes.
Implementation Method 1
incorporates a ball-mill mechanism into the ALD technique
Implementation Method 2
Atomic layer deposition (ALD) as a technique has been considered an effective method to achieve uniform and homogeneous coating on a substrate
Data Source
AI summary
Cathode materials, batteries, and methods of forming one or more electrodes for batteries are disclosed. In some embodiments, a coated lithium battery cathode material includes coated single crystalline primary particles, the coated single crystalline primary particles including single crystalline primary particles of a lithium transition metal oxide, a first sub-nanoscale lithium metal oxide coating on the single crystalline primary particles wherein the first sub-nanoscale lithium metal oxide is less than 1 nm thick, and a carbon coating disposed on the first sub-nanoscale lithium metal oxide coating to form coated single crystalline primary particles.