Sacrificial Salt Coated Current Collector for Battery Capacity Retention
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Solution Overview
Problem
Ion insertion and deinsertion batteries, such as lithium-ion batteries, face significant irreversible capacity loss during the first charge cycle due to passivation layer formation and surface reactions, leading to reduced energy density and performance.
Innovation Solution
A current collector coated with a non-active layer containing an organic binder and a sacrificial salt, which decomposes to compensate for irreversible ion consumption and maintain electrode integrity, thereby reducing morphological modifications and enhancing capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional lithium is introduced into the electrode to compensate for irreversible capacity loss, then capacity retention is improved, but device complexity increases due to requiring special deposition equipment and processes
Solution Approach 1:
The patent applies preliminary action by incorporating a sacrificial salt layer into the current collector before electrode assembly. This layer proactively provides lithium ions during the first charge cycle to compensate for irreversible capacity loss, eliminating the need for complex post-assembly lithium deposition equipment and processes while improving capacity retention
Solution Approach 2:
The sacrificial salt layer acts as an intermediary between the current collector and the electrode. It mediates the lithium ion supply by decomposing to release lithium ions that compensate for irreversible losses, simplifying the overall system by replacing complex deposition equipment with a passive chemical layer
2Reliability
If sacrificial salt is deposited directly on the electrode, then ion compensation is achieved, but manufacturing precision decreases due to difficulty in controlling deposition uniformity and thickness
Solution Approach 1:
The patent segments the sacrificial salt deposition into two distinct stages: first depositing the salt layer onto the current collector where uniformity is easier to control, then assembling the electrode separately. This segmentation eliminates the difficulty of controlling thin salt layer deposition on delicate electrode surfaces while maintaining effective ion compensation
Solution Approach 2:
The current collector serves as an intermediary substrate for sacrificial salt deposition. By depositing the salt on the robust current collector rather than directly on the electrode, the system achieves better deposition uniformity and thickness control, as the current collector provides a more forgiving surface for manufacturing processes
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 reduces irreversible capacity loss by up to 10% and improves the energy density of the battery by providing a reserve of ions and promoting adhesion and corrosion resistance, while maintaining electrode performance.
Implementation Method 1
which salt is a sacrificial salt... during the first charge, when the active material of the negative electrode is brought to a lithium insertion potential, some of the lithium reacts with the electrolyte on the surface of the active material grains to form a passivation layer
Implementation Method 2
accumulators operating on the principle of ionic insertion and disinsertion in the active material of the electrode... the negative electrode will incorporate lithium into the network of the material constituting it
Implementation Method 3
The invention also tends towards reducing the morphological modifications of the electrode... promoting adhesion and corrosion resistance
Implementation Method 4
promoting adhesion and corrosion resistance... while maintaining electrode performance
Data Source
Figure 1
AI summary
The invention relates to a current collector for an accumulator with ion insertion or deinsertion, said collector being coated on at least one of the faces thereof with an inactive layer intended for providing a junction between said current collector and an electrode, said inactive layer comprising at least one organic binder and at least one salt, one of the ions of which is that which is involved in the process of ion insertion or deinsertion in the active material of the electrode.