Pre-Formed Anode SEI Composition for Lower First-Cycle Lithium Loss
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Solution Overview
Problem
Conventional lithium-ion batteries face challenges with capacity loss and reduced cyclability due to the formation of a solid electrolyte interphase (SEI) on the negative electrode during initial cycling, which increases impedance and resistance.
Innovation Solution
A method is developed to pre-form anode particles with a solid electrolyte interphase (SEI) using a dispersion containing anode precursor particles, a liquid electrolyte solution, and an additive not found in the lithium ion battery. A voltage or current is applied to form the SEI on the anode particles, which are then recovered and used in the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SEI forms during initial battery cycling, then the negative electrode is protected from further electrolyte decomposition, but the battery experiences increased impedance and resistance leading to capacity loss
Solution Approach 1:
The patent applies preliminary action by pre-forming the SEI layer on anode particles before they are assembled into the battery. The anode particles are pre-coated with SEI-forming additives in a controlled environment, allowing the protective layer to form in advance. This eliminates the need for SEI formation during initial battery cycling, thereby preventing capacity loss and impedance increase while maintaining the protective function.
2Reliability
If SEI forms on the negative electrode during initial cycling, then electron-insulating protection is provided, but irreversible capacity loss occurs
Solution Approach 1:
The protective SEI layer is formed in advance on the anode particles during a pre-treatment process before battery assembly. This preliminary formation allows the anode to acquire its protective electron-insulating layer without undergoing the capacity loss that would occur during initial battery cycling, thus preserving lithium capacity while maintaining protection.
3Adaptability or versatility
If conventional in-situ SEI formation is used during battery cycling, then the SEI composition is determined by battery operating conditions, but desired SEI compositions cannot be achieved
Solution Approach 1:
The patent enables precise control of SEI composition by pre-forming the layer under controlled laboratory conditions before battery assembly. Specific additives and formulations can be applied to the anode particles to create SEI layers with exact desired compositions, independent of subsequent battery operating conditions. This preliminary formation ensures reproducible, precise SEI composition while maintaining adaptability to different battery applications.
Solution Approach 2:
The patent applies parameter changes by controlling the pre-formation process parameters (additive concentration, temperature, time, voltage) to achieve desired SEI compositions. By adjusting these parameters during the pre-treatment stage, precise control over SEI properties is achieved, enabling tailoring of the layer for specific battery performance requirements.
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 pre-formed SEI on anode particles reduces capacity loss, increases the first cycle Coulombic efficiency, and minimizes active lithium loss, while enabling the formation of SEI compositions that cannot be achieved through in-situ formation during battery cycling.
Implementation Method 1
A voltage or a current is applied across the dispersion to form the anode particles bearing the solid electrolyte interphase
Data Source
AI summary
A method is provided for pre-forming anode particles for use in lithium ion batteries. The pre-formed anode particles bear a solid electrolyte of a composition that cannot be formed in situ in the battery. The method includes providing a dispersion of anode precursor particles and an additive not found in the battery in a liquid electrolyte solution. Applying a voltage or current across the dispersion forms the solid electrolyte interphase, on the particles. These particles can be used in an electrode of a lithium ion battery.