Metal-Oxygen Battery Electrode Coating for Voltage Hysteresis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-oxygen batteries face challenges such as dendrite formation, moisture protection, voltage hysteresis, and capacity decay due to mechanical stresses and poor contact between discharge products and the conducting matrix, limiting their specific energy and cycle life.
Innovation Solution
A metal/oxygen electrochemical cell with a protective oxide layer, such as TiO2 or SiO2, deposited using atomic layer deposition on the porous electrically conductive material to prevent parasitic reactions and maintain electronic transport, along with a porous separator and electrolyte solution containing LiPF6 in organic solvents, to enhance discharge product deposition and reduce hysteresis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a high-capacity positive electrode active material such as Li2O, FeF3, or BiF3 is used to increase specific energy, then the theoretical specific energy increases above 800 Wh/kg, but the material reacts with lithium at a lower voltage which limits the practical specific energy
Solution Approach 1:
The patent changes the voltage parameter by using a conventional lithium-intercalating oxide positive electrode (such as LiCoO2, LiNi0.8Co0.15Al0.05O2, or Li1.1Ni0.3Co0.3Mn0.3O2) that operates at higher voltages (above 3.7V vs. Li/Li+), thereby avoiding the voltage limitation issue of high-capacity materials like Li2O, FeF3, and BiF3 that react at lower voltages
2Quantity of substance
If lithium metal is used in the negative electrode to achieve high specific capacity of 3863 mAh/g, then the specific capacity increases significantly compared to conventional lithium-ion electrodes, but dendrite formation occurs which limits cycle life and reliability
Solution Approach 1:
The patent uses a conventional lithium-ion negative electrode (such as graphite, silicon, or tin) instead of lithium metal, accepting the trade-off of lower specific capacity (280-350 mAh/g) in exchange for significantly improved cycle life and reliability, as lithium-ion electrodes do not suffer from dendrite formation
Solution Approach 2:
The patent employs composite negative electrode materials such as silicon-graphite composites or tin-oxide coatings on graphite, which combine the high capacity benefits of silicon/tin with the structural stability and cycle life of graphite, achieving a balance between specific capacity and reliability
3Quantity of substance
If the positive electrode porosity is increased to allow Li2O2 deposition and achieve high capacity, then the capacity increases, but mechanical stresses cause poor contact between discharge products and the conducting matrix leading to capacity decay
Solution Approach 1:
The patent uses a porous conducting matrix (such as carbon black, graphite, carbon fibers, or carbon nanotubes) with optimized porosity (40-80%) that provides sufficient space for discharge product deposition while maintaining structural integrity and good contact between discharge products and the conducting matrix, preventing capacity decay
Solution Approach 2:
The patent employs composite positive electrode materials combining the porous conducting matrix with lithium-intercalating oxide particles (such as LiCoO2, LiNi0.8Co0.15Al0.05O2, or Li1.1Ni0.3Co0.3Mn0.3O2), creating a structured composite that maintains both high capacity and good electrical contact during cycling
4Reliability
If conventional lithium-ion batteries are used with limited capacity positive electrodes to achieve practical capacity of 180-250 mAh/g, then the cycle life and reliability are maintained, but the specific energy is limited to below 500 Wh/kg
Solution Approach 1:
The patent changes the positive electrode material parameters by using advanced lithium-intercalating oxides with higher operating voltages (above 3.7V vs. Li/Li+) and optimized compositions (such as LiNi0.8Co0.15Al0.05O2 or Li1.1Ni0.3Co0.3Mn0.3O2), which increase the specific energy to above 500 Wh/kg while maintaining good cycle life and reliability through conventional lithium-ion mechanisms
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 the round-trip efficiency and cycle life of the metal/oxygen battery by reducing voltage hysteresis and capacity decay, enabling higher specific energy and power output.
Implementation Method 1
A metal/oxygen electrochemical cell with a protective oxide layer, such as TiO2 or SiO2, deposited using atomic layer deposition on the porous electrically conductive material
Implementation Method 2
to prevent parasitic reactions and maintain electronic transport
Implementation Method 3
a porous separator and electrolyte solution containing LiPF6 in organic solvents
Implementation Method 4
electrolyte solution containing LiPF6 in organic solvents
Implementation Method 5
The separator contains an electrolyte with a lithium cation, and serves as a physical barrier between the electrodes such that none of the electrodes are electronically connected within the cell
Implementation Method 6
In some cases the negative electrode may include lithium metal, which can be electrochemically dissolved and deposited reversibly
Implementation Method 7
there is extraction via oxidation of lithium ions from the active material of the positive electrode
Implementation Method 8
there is reduction of lithium ions into the active material of the negative electrode
Implementation Method 9
there is generation of electrons at the positive electrode and consumption of an equal amount of electrons at the negative electrode, and these electrons are transferred via an external circuit
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
In one embodiment, a metal/oxygen electrochemical cell includes a negative electrode, a separator positioned adjacent to the negative electrode, a positive electrode spaced apart from the negative electrode by the separator, the positive electrode including a porous electrically conductive material portion, the porous electrically conductive material portion coated with a conformally coated protective layer, and an electrolyte within the porous electrically conductive material portion.