Bi Alloy Electrode Structure With Halide Solid Electrolyte

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Solution Overview

Problem

Lithium secondary batteries face challenges with low charge-discharge efficiency and poor cycle characteristics due to lithium dendrite deposition and expansion/contraction of alloy electrodes, which degrade current collecting properties and limit capacity density.

Innovation Solution

A battery structure featuring a first electrode with a porous substrate and a Bi active material layer, using a solid electrolyte with a halide solid electrolyte, which improves specific surface area and reduces degradation by forming a Bi plating layer on the substrate, enhancing charge-discharge characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If alloy materials (Si, Sn, Al) are used to increase capacity density, then battery capacity is improved, but lithium dendrite deposition occurs causing poor cycle characteristics

Engineering Contradiction:

Improvebattery capacityVSAvoidcycle characteristics

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A solid electrolyte layer is introduced as an intermediary between the alloy-based active material and the liquid electrolyte. This solid electrolyte layer prevents direct contact and harmful interactions while allowing ionic transport, thereby suppressing lithium dendrite deposition and improving cycle characteristics while maintaining the high capacity benefits of alloy materials.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the physical state parameter of the electrolyte from liquid to solid form in the vicinity of the electrode. This parameter change fundamentally alters the interface behavior, preventing dendrite formation and improving battery reliability while preserving the high capacity density achieved through alloy material usage.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If alloy electrodes are used to increase capacity, then battery capacity is improved, but expansion/contraction degrades current collecting properties

Engineering Contradiction:

Improvebattery capacityVSAvoidcurrent collecting properties

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The electrode structure is designed with spatially differentiated functions: the active material layer contains the alloy material for high capacity, while a separate solid electrolyte layer provides structural stability and maintains good contact. This local quality differentiation allows the alloy to expand/contract without compromising the overall electrode's current collecting properties.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The electrode is constructed as a composite structure combining alloy-based active material with a solid electrolyte layer. This composite design allows the alloy component to provide high capacity through expansion/contraction mechanisms while the solid electrolyte component maintains structural integrity and electrical connectivity, preventing degradation of current collecting properties.

Inventive Principle:

Principle #40Composite materials

3Productivity

If porous substrate is used to increase specific surface area, then charge-discharge characteristics are improved, but manufacturing complexity increases

Engineering Contradiction:

Improvecharge-discharge characteristicsVSAvoidstructure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The electrode is segmented into distinct functional layers: a porous substrate layer that provides high specific surface area for improved charge-discharge characteristics, and a solid electrolyte layer that simplifies the overall structure by eliminating the need for complex binder and conductive additive systems. This segmentation allows each layer to be optimized independently while maintaining manufacturing feasibility.

Inventive Principle:

Principle #1Segmentation

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 battery exhibits improved charge-discharge efficiency and cycle characteristics, maintaining initial capacity and efficiency even after multiple cycles, with the Bi active material layer adhering well to the substrate and reducing degradation.

Implementation Method 1

a solid electrolyte layer disposed between the first electrode and the second electrode, in which the solid electrolyte layer contains a first solid electrolyte

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

the active material layer contains Bi... electrodes containing aluminum, silicon, tin, or the like that electrochemically alloys with lithium during charging

Methodology Applied

Scientific EffectElectrochemical alloying: Absorption (physical)

Implementation Method 3

a substrate including a porous body

Methodology Applied

Scientific EffectPorosity: Porosity

Data Source

PatentUS20240162486A1battery

Publication Date: 2024.05.16 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A battery includes a first electrode; a second electrode; and a solid electrolyte layer disposed between the first electrode and the second electrode. The solid electrolyte layer contains a first solid electrolyte. The first electrode includes: a substrate including a porous body; and an active material layer disposed on a surface of the substrate. The active material layer contains Bi. The first solid electrolyte contains a halide solid electrolyte.