Polymer-Inorganic SEI Composition for Lean-Electrolyte Lithium Metal Batteries
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Solution Overview
Problem
Lithium metal batteries face instability due to the mechanically unstable solid-electrolyte interphase (SEI) layer, leading to rapid battery failure and low efficiency, as it constantly reforms and consumes electrolyte, necessitating a stable and controlled SEI for improved cycling stability and energy density.
Innovation Solution
A reactive polymer composite with functionalized polymer chains and fillers like graphene oxide is used to form a stable polymeric metal salt SEI layer, which reacts with the lithium electrode to create a defect-free morphology and prevent electrolyte loss, maintaining stability over 600 charge/discharge cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrolyte-derived SEI is used to stabilize Li anode, then Li electrode stability is improved, but SEI mechanical stability deteriorates causing constant reforming and electrolyte consumption
Solution Approach 1:
The patent changes the chemical composition parameters of the SEI layer by using polymer precursors with specific functional groups (carboxylic acid, sulfonic acid, phosphoric acid) that react with Li metal to form stable polymeric metal salts. This chemical parameter change transforms the SEI from an unstable electrolyte-derived layer to a stable polymer-based layer that resists mechanical degradation during cycling.
Solution Approach 2:
The patent creates a composite SEI structure by combining polymer materials with inorganic fillers (such as Al2O3, SiO2, TiO2, or graphene oxide) to form a mechanically robust and chemically stable interphase. This composite approach provides both the chemical stability of polymers and the mechanical strength of inorganic materials, preventing SEI cracking and dendrite growth.
2Stability of the object's composition
If ex-situ fabricated protective layers (inorganic salts, Li-alloys, polymers) are used to replace electrolyte-derived SEI, then SEI stability is improved, but layer integrity deteriorates causing cracks and triggering Li-electrolyte reactions
Solution Approach 1:
The patent employs polymer-based SEI layers that possess inherent flexibility and elasticity, allowing the SEI to accommodate the volume changes and morphological fluctuations of the Li anode during cycling without cracking. This flexible polymer matrix, potentially combined with flexible inorganic components like graphene oxide, maintains layer integrity while providing stable protection.
Solution Approach 2:
The patent creates a composite SEI structure by combining polymer materials with inorganic fillers (such as Al2O3, SiO2, TiO2, or graphene oxide) to form a mechanically robust and chemically stable interphase. This composite approach provides both the chemical stability of polymers and the mechanical strength of inorganic materials, preventing SEI cracking and dendrite growth.
3Reliability
If large excess of electrolyte is used to achieve cycling stability, then battery reliability is improved, but energy density deteriorates
Solution Approach 1:
The patent performs preliminary action by forming a stable, protective polymer-based SEI layer during the initial cycles that prevents subsequent electrolyte decomposition and consumption. This pre-formed stable interphase eliminates the need for continuous electrolyte replenishment, enabling cycling stability with minimal electrolyte quantities and thus high energy density.
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 reactive polymer composite achieves a stable SEI layer that enhances lithium deposition efficiency, reduces electrolyte consumption, and maintains high energy density by preventing electrolyte loss, with a coulombic efficiency greater than 95% and electrolyte retention of at least 70% after 100 cycles.
Implementation Method 1
one, or more functional groups configured to electrochemically decompose
Implementation Method 2
functional groups that are configured to react with a metal electrode to form a polymeric metal salt
Data Source
AI summary
Disclosed is a reactive polymer composite comprising a reactive functionalized polymer having a main polymer chain with functionalization along the main polymer chain, wherein the functionalization comprises one or more functional groups that are configured to react with a metal electrode to form a polymeric metal salt and one, or more functional groups configured to electrochemically decompose. Also disclosed are electrodes and batteries comprising the same. Also disclosed are methods of making the same.