Battery Additives That Release Donor Ions for SEI Capacity Loss
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Solution Overview
Problem
Existing metal-ion batteries face challenges in achieving higher specific capacities due to insufficient content of metal ions available for reversible electrochemical reactions, particularly during the formation of a solid electrolyte interphase (SEI) in the first cycle.
Innovation Solution
Incorporating 'donor' metal ions, such as Li ions, into metal-ion batteries through additives in the electrolyte, electrodes, or separator, which decompose to release additional metal ions during the battery's operation, thereby enhancing metal content and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal or powder is added to compensate for lithium loss during SEI formation, then the metal ion content is increased, but the fabrication cost increases due to dry room requirements and safety hazards are introduced
Solution Approach 1:
The patent uses sacrificial salt additives that decompose during the first charge cycle to release metal ions. These additives are consumed in a controlled manner during initial cycles to compensate for SEI formation losses, then cease to interfere with normal battery operation. This disposable approach avoids the need for expensive dry room fabrication while providing the necessary metal ion supplementation.
Solution Approach 2:
The patent introduces sacrificial salt additives as intermediary substances that mediate between the electrode materials and the electrolyte. These additives temporarily provide metal ions during SEI formation and then decompose into harmless byproducts, serving as a bridge that enables high-capacity electrode materials to function without requiring complex fabrication environments.
2Productivity
If high capacity electrode materials are used to increase specific capacity, then the energy density is improved, but the cycle stability deteriorates due to insufficient metal ions for reversible reactions
Solution Approach 1:
The patent applies preliminary action by providing sacrificial salt additives that release metal ions during the first charge cycle before normal battery operation begins. This preliminary supplementation ensures that sufficient metal ions are available for SEI formation and initial cycling, establishing a stable foundation for subsequent reversible reactions and improving long-term cycle stability.
Solution Approach 2:
The patent changes the parameter of metal ion availability by introducing sacrificial salts that dynamically release ions during initial cycles. This parameter change transforms the system from one with fixed, insufficient metal ion content to one where metal ion availability is temporarily enhanced during critical early operation, enabling high-capacity materials to achieve their full potential with improved cycle stability.
3Quantity of substance
If lithium powder is used to compensate for lithium loss, then the metal ion supply is increased, but safety hazards are introduced
Solution Approach 1:
The patent replaces hazardous lithium powder with sacrificial salt additives that are chemically stable during storage and handling. These salts decompose in a controlled manner during the first charge cycle to release metal ions, then are converted into stable, non-hazardous byproducts. This disposable salt-based approach eliminates the safety hazards associated with handling and storing reactive lithium powder while maintaining effective metal ion supplementation.
Solution Approach 2:
The patent converts the potentially harmful reaction of sacrificial salts into a beneficial process. The decomposition of sacrificial salts during initial cycling, which could be seen as a loss of additive material, is actually harnessed to provide necessary metal ions for SEI formation and capacity compensation. The harmful-reactive nature of lithium powder is replaced by the controlled, benign decomposition of salt additives that yield the same beneficial effect without safety risks.
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 increases the total useful energy density of the battery after the formation cycle by providing additional metal ions, improving cycle stability, rate performance, and capacity retention, especially at elevated temperatures.
Implementation Method 1
the decomposition of such sacrificial salts results in the release of Li to be incorporated into the electrode
Implementation Method 2
applying a potential between the one of the battery electrodes and a counter electrode the decomposition of such sacrificial salts results in the release of Li
Implementation Method 3
additional donor ions corresponding to the metal ions stored and released by anode and cathode active material particles
Implementation Method 4
Gaseous products that are not harmful for the battery components may be evacuated from the battery during or after this decomposition process
Data Source
AI summary
Metal-ion battery cells are provided that take advantage of the disclosed “doping” process. The cells may be fabricated from anode and cathode electrodes, a separator, and an electrolyte. A metal-ion additive may be incorporated into (i) one or more of the electrodes, (ii) the separator, or (iii) the electrolyte. The metal-ion additive provides additional donor ions corresponding to the metal ions stored and released by anode and cathode active material particles. An activation potential may then be applied to the anode and cathode electrodes to release the additional donor ions into the battery cell.