Lithiation Additive for Solid-State Battery Gel Electrolyte
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Solution Overview
Problem
Lithium-ion batteries experience permanent lithium ion loss due to conversion reactions and solid electrolyte interphase (SEI) formation, leading to decreased specific energy and power capacity.
Innovation Solution
Incorporating a lithium-source material with a high theoretical specific capacity, such as lithium sulfide, into the positive electrode, coated on or dispersed with electroactive solid-state particles, and using a polymeric gel electrolyte to fill voids between these particles, which also serves as a lithium reservoir to compensate for irreversible lithium loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lithium-ion batteries are used, then initial capacity is achieved, but permanent lithium ion loss occurs due to conversion reactions and SEI formation, leading to decreased specific energy and power capacity
Solution Approach 1:
The patent applies preliminary action by incorporating a lithium-source material (such as lithium sulfide) into the positive electrode structure before battery operation begins. This pre-positioned lithium reservoir compensates for the lithium ions that will be permanently lost during cycling due to SEI formation and conversion reactions, thereby maintaining capacity and improving cycle stability without requiring external intervention during operation.
Solution Approach 2:
The patent implements the discarding and recovering principle by using a lithium-source material that can release lithium ions back into the system. When lithium ions are lost to SEI formation or conversion reactions, the lithium-source material serves as a replenishment source, effectively recovering the lost lithium capacity and maintaining overall battery performance over extended cycling.
2Reliability
If lithium-source material is incorporated into the positive electrode, then capacity loss is reduced through lithium replenishment, but electrode structure complexity increases
Solution Approach 1:
The patent applies merging by integrating the lithium-source material directly into the positive electrode structure, combining the functions of energy storage and lithium replenishment within a single electrode component. This eliminates the need for separate lithium reservoirs or additional components, thereby reducing overall device complexity while maintaining capacity retention benefits.
Solution Approach 2:
The positive electrode in the patent achieves multi-functionality by simultaneously serving as an energy storage component and a lithium-source reservoir. The electrode not only stores lithium ions for normal operation but also replenishes lithium ions lost during cycling, thereby improving capacity retention without requiring additional dedicated components.
3Reliability
If polymeric gel electrolyte is used to fill voids between particles, then ionic conductivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes porous materials by incorporating a polymeric gel electrolyte that fills the void spaces between solid-state particles in the electrode structure. This gel electrolyte penetrates the porous network formed by particle arrangements, providing continuous ionic conduction pathways and improving overall ionic conductivity while accommodating the inherent porosity of the electrode structure.
Solution Approach 2:
The patent applies composite materials by combining solid-state particles with a polymeric gel electrolyte to form a composite electrode structure. This composite approach leverages the advantages of both components: the solid-state particles provide structural integrity and electroactive sites, while the gel electrolyte fills voids and enhances ionic conductivity, creating a synergistic material system.
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 enhances the cycle stability and maintains battery capacity by utilizing the lithium-source material to replenish lost lithium during cycling, thereby reducing capacity loss over time.
Implementation Method 1
The electrolyte is suitable for conducting lithium ions between the electrodes
Implementation Method 2
a portion of the lithium ions remains with the negative electrode following the first cycle due to, for example, conversion reactions
Implementation Method 3
the formation of a solid electrolyte interphase (SEI) layer on the negative electrode during the first cycle
Implementation Method 4
the negative electrode may contain a comparatively high concentration of intercalated lithium, which is oxidized into lithium ions releasing electrons
Implementation Method 5
Such lithium ions may be assimilated into the material of the positive electrode by an electrochemical reduction reaction
Data Source
AI summary
A positive electrode including an active layer is provided, where the active layer includes a plurality of positive electroactive solid-state particles, a lithium-source material coated on or dispersed with the positive electroactive solid-state particles in the active layer, and a polymeric gel electrolyte at least partially filling voids between the positive electroactive solid-state particles in the active layer. The lithium-source material having a theoretical specific capacity greater than or equal to about 100 mAh/g to less than or equal to about 3,000 mAh/g.