Core-Shell Composite Cathodes for Low-Impedance Solid-State Batteries

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Solution Overview

Problem

Solid-state batteries face high cell impedance due to poor contact between active intercalation cathode material and ionically conductive catholyte material, unhomogenized mixture of active cathode, catholyte, and electronically conductive additive materials, and the use of a binding polymer material.

Innovation Solution

The formation of core-shell structures with a core of active cathode material and a shell of ionically conductive catholyte and electronically conductive additive, achieved through mechanical mixing or milling followed by an energy-assisted solvent-free spray process, to create a more uniform shell around the core, thereby improving contact and reducing impedance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional mixing methods are used to combine active cathode material, catholyte, and electronically conductive additive, then the manufacturing process is simple, but the mixture is unhomogenized leading to poor contact between materials

Engineering Contradiction:

Improvehomogeneity of mixtureVSAvoidcomplexity of mixing process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The cathode is segmented into core-shell structures where the core is active cathode material and the shell is a homogeneous mixture of catholyte and electronically conductive additive. This segmentation ensures uniform distribution of materials at the particle level, improving contact between components while maintaining manufacturing simplicity through a straightforward coating process.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The shell structure provides local quality enhancement by concentrating the ionically conductive catholyte and electronically conductive additive specifically at the interface between the active cathode material and the electrolyte. This localized distribution ensures optimal contact zones without requiring complex bulk mixing, thereby improving homogeneity where it matters most.

Inventive Principle:

Principle #3Local quality

2Reliability

If binding polymer material is used in the composite cathode, then the structural integrity is improved, but the cell impedance increases

Engineering Contradiction:

Improvecell impedanceVSAvoidstructural integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The invention extracts and eliminates the binding polymer material from the composite cathode structure. Instead of using a polymer binder to hold materials together, the core-shell particle structure itself provides the necessary structural integrity, while the shell ensures good contact between materials. This removal of polymer binder directly reduces cell impedance while maintaining structural stability through the engineered core-shell architecture.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The core-shell structure functions as a composite material system where the core (active cathode material) and shell (catholyte + electronically conductive additive) work together to provide both structural integrity and electrical/ionic conductivity. This composite approach replaces the need for separate binding polymers, reducing impedance while maintaining mechanical strength.

Inventive Principle:

Principle #40Composite materials

3Manufacturing precision

If core-shell structures with uniform shell are created using energy-assisted solvent-free spray process, then the contact between cathode materials is improved, but the manufacturing complexity increases

Engineering Contradiction:

Improveuniformity of shell coatingVSAvoidease of spray processing

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The energy-assisted solvent-free spray process changes key processing parameters by eliminating solvents and using energy assistance (such as thermal or kinetic energy) to achieve uniform shell coating. This parameter change allows for precise control of shell thickness and composition, ensuring homogeneous material distribution and improved interfacial contact, while the solvent-free nature simplifies downstream drying and processing steps.

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 enhances the power rates and cycle life of solid-state batteries by ensuring a homogeneous mixture and improved contact between cathode materials, resulting in reduced cell impedance.

Implementation Method 1

a composite cathode layer formed onto a positive current collector using an energy-assisted solvent-free spray process

Methodology Applied

Scientific EffectSpray deposition: Spray

Data Source

PatentUS12451477B1Cathode-catholyte core-shell structures, composite cathode layers, and solid-state batteries, and methods for manufacturing of the same

Publication Date: 2025.10.21 AMPCERA INC

AI summary

A solid-state battery, including: an anode layer; a solid-state ionic conductive membrane layer; and a composite cathode layer formed onto a positive current collector using an energy-assisted solvent-free spray process. The composite cathode includes core-shell structures, wherein the core is the active cathode material, and the shell is a mixture of ionically conductive catholyte and an electronically conductive additive.