Liquid Additive Electrolyte for Low-Pressure Solid-State Batteries

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Solution Overview

Problem

All-solid-state batteries face challenges in maintaining ionic conductivity and current density robustness under conditions of room temperature and low clamping pressure due to voids created by volume changes in the electrodes, which block lithium ion conduction paths.

Innovation Solution

A liquid additive comprising a lithium salt and a solvent, such as orthoformate-based compounds, is introduced to fill voids within the solid electrolyte layers, enhancing lithium ion conductivity and reducing reactivity with solid electrolytes, thereby improving battery performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a solid electrolyte layer is used in an all-solid-state battery, then safety is improved (lower fire and explosion risk), but ionic conductivity decreases due to voids between the solid electrolyte and electrodes

Engineering Contradiction:

ImprovesafetyVSAvoidionic conductivity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent uses a composite electrolyte system combining solid electrolyte particles with liquid electrolyte. The solid electrolyte provides safety benefits while the liquid electrolyte fills voids to maintain ionic conductivity. This composite approach allows the battery to achieve both safety improvements and adequate ionic conductivity by leveraging the complementary strengths of both electrolyte types.

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If clamping pressure is reduced for commercialization, then ease of operation is improved, but voids generated by volume change cannot be recovered, blocking lithium ion conduction paths

Engineering Contradiction:

Improveclamping pressureVSAvoidcurrent density robustness

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent employs liquid electrolyte to fill voids in the solid electrolyte layer, utilizing the fluid properties of liquids to adapt to volume changes and maintain contact between solid electrolyte particles and electrodes. The liquid electrolyte can flow into and fill gaps created by volume expansion/contraction during charge-discharge cycles, ensuring continuous ionic conduction paths without requiring high clamping pressure.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the physical state parameter of the electrolyte system by incorporating a liquid component alongside solid electrolyte particles. This parameter change allows the electrolyte to transition from a rigid solid structure to a more flexible composite system where the liquid phase can dynamically fill voids and maintain ionic conductivity under varying pressure conditions.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If an anodeless all-solid-state battery is used, then device complexity is reduced (no anode active material needed), but voids between solid electrolyte layer and anode current collector prevent uniform lithium metal precipitation

Engineering Contradiction:

Improveanode structureVSAvoidlithium precipitation uniformity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The liquid electrolyte fills the voids between the solid electrolyte layer and the anode current collector, creating a fluid medium that facilitates uniform lithium ion distribution and precipitation. The liquid phase allows lithium ions to move freely and deposit uniformly on the current collector surface, overcoming the contact issues that would arise with solid-solid interfaces alone.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 liquid additive enables stable operation of all-solid-state batteries at room temperature and low clamping pressure by maintaining lithium ion conductivity and reducing interfacial resistance, thus enhancing current density and overall battery performance.

Implementation Method 1

improve ionic conductivity and current density robustness

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

A liquid additive comprising a lithium salt and a solvent, such as orthoformate-based compounds, is introduced to fill voids within the solid electrolyte layers

Methodology Applied

Scientific EffectSolvation: Solvation

Implementation Method 3

maintaining lithium ion conductivity and reducing interfacial resistance, thus enhancing current density and overall battery performance

Methodology Applied

Scientific EffectInterfacial resistance reduction: Conduction (electrical)

Data Source

PatentUS20250246673A1Liquid additive with high lithium ion conductivity and low reactivity with solid electrolyte, and all-solid-state battery capable of operating at room temperature and low pressure including same

Publication Date: 2025.07.31 HYUNDAI MOTOR CO LTD

AI summary

A liquid additive for an all-solid-state battery capable of operating under conditions of room temperature and low pressure, and an all-solid-state battery including the same. Specifically, by adding a liquid additive having low reactivity with a solid electrolyte and high lithium ion conductivity to an anode layer, a cathode layer, or a solid electrolyte layer, ionic conductivity and current density robustness of the all-solid-state battery can be improved under conditions of room temperature and low pressure.