Semi-Solid Battery Electrolyte Sequencing for Low Impedance

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Solution Overview

Problem

Traditional lithium ion batteries face challenges in achieving high energy density due to safety hazards such as volume expansion and metal dendrite growth, especially when using silicon or lithium metal anodes with liquid electrolytes, which lead to increased impedance and safety risks.

Innovation Solution

A method for preparing in-situ polymerized semi-solid state batteries involves injecting a lithium battery liquid electrolyte, followed by a mixture of polymer monomers, plasticizers, and initiators, specifically vinylene carbonate and tripropargyl phosphate, to form a gel electrolyte, reducing impedance and enhancing safety through optimized electrolyte formulation and manufacturing processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional in-situ polymerization method is used, then semi-solid state battery can be prepared, but polymer participates in anode SEI film composition causing significant increase in battery impedance

Engineering Contradiction:

Improvebattery safetyVSAvoidbattery impedance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The electrolyte system is segmented into two distinct components: liquid electrolyte injected first, and polymer monomers injected second. This temporal and functional segmentation prevents polymer participation in SEI film formation while allowing liquid electrolyte to establish proper initial SEI composition, thereby reducing impedance while maintaining safety benefits

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Liquid electrolyte is injected and allowed to form proper SEI film on the anode before polymer monomers are introduced. This preliminary action ensures that the SEI film is already established with appropriate composition before polymerization begins, preventing polymer contamination of the SEI layer and reducing impedance

Inventive Principle:

Principle #10Preliminary action

2Use of energy by moving object

If high-nickel ternary lithium battery with high specific capacity anode materials is used, then specific energy density is improved, but safety hazards increase due to high activity

Engineering Contradiction:

Improvespecific energy densityVSAvoidbattery safety

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The battery uses a composite electrolyte system combining liquid electrolyte and polymer gel, where the liquid component provides good ionic conductivity for high energy density operation, while the polymer gel component provides structural stability and safety benefits, creating a synergistic composite that achieves both high energy density and improved safety

Inventive Principle:

Principle #40Composite materials

3Use of energy by moving object

If liquid electrolyte is used with silicon or lithium metal anode, then high energy density is achieved, but volume expansion and metal dendrite growth cause safety hazards

Engineering Contradiction:

Improveenergy densityVSAvoidvolume expansion and dendrite growth

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The electrolyte undergoes a parameter change from purely liquid state to a semi-solid gel state through in-situ polymerization. This parameter change transforms the electrolyte's physical properties, providing mechanical support to constrain anode volume expansion and suppress dendrite growth, while maintaining the ionic conductivity needed for high energy density

Inventive Principle:

Principle #35Parameter changes

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 significantly reduces battery impedance, improves energy density, and enhances safety by stabilizing the anode structure and preventing metal dendrite growth, resulting in a semi-solid state battery with performance comparable to liquid batteries.

Implementation Method 1

S5: aging, and in-situ polymerization to form gel, thus obtaining the semi-solid state battery

Methodology Applied

Scientific EffectIn-situ polymerization: Photopolymerisation

Data Source

PatentUS20240291030A1Method for Preparing In-Situ Polymerized Semi-Solid State Battery

Publication Date: 2024.08.29 REPT BATTERO ENERGY CO LTD

AI summary

A method for preparing an in-situ polymerized semi-solid state battery, comprising the following steps: assembling: assembling a cathode plate, a separator and an anode plate into a case to form a dummy cell; first injection: injecting a lithium battery liquid electrolyte; aging and formation; second injection: injecting a mixture of polymer monomers, a plasticizer and an initiator, wherein the polymer monomers are a combination of vinylene carbonate and tripropargyl phosphate; aging, and in-situ polymerization at 58-65° C. to form gel, thus obtaining a low impedance semi-solid state battery. The formulation of the second injection comprises a tridimensional monomer, and the liquid electrolyte can be locked in the three-dimensional structure after crosslinking. Compared with a chain polymer, fewer polymers can be used to achieve the gel effect, the formed gel structure is more stable and possesses better thermal stability, and at the same time, the liquid component is higher, and the impedance is lower, so that the semi-solid state battery with low impedance is obtained.