Lithium Microsphere Anodes With Dual Electrolytes Against Dendrites

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Solution Overview

Problem

Lithium metal batteries face widespread adoption limitations due to non-uniform electrodeposition leading to dendrite formation, which causes battery deterioration and short-circuiting.

Innovation Solution

The implementation of lithium metal microspheres embedded in an ion and electron conducting oxide-based material with a sulfide-based and oxide-based solid electrolyte layer configuration, forming a size or concentration gradient and localized solid electrolyte interface to prevent dendrite growth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If lithium metal is used in solid-state batteries to achieve higher energy density, then volumetric and gravimetric energy densities are improved, but non-uniform electrodeposition occurs leading to dendrite formation

Engineering Contradiction:

Improveenergy densityVSAvoiddendrite formation

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The lithium metal anode is segmented into multiple small lithium microspheres (0.5-4 microns in diameter) rather than using a continuous lithium metal layer. This segmentation distributes the electrodeposition sites uniformly, preventing localized dendrite growth while maintaining high energy density.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each lithium microsphere is surrounded by a localized solid electrolyte interface (SEI) layer, creating uniform local conditions for lithium deposition. The SEI layer forms a protective barrier around each microsphere, ensuring controlled and uniform electrodeposition that prevents dendrite formation.

Inventive Principle:

Principle #3Local quality

2Reliability

If lithium microspheres are used to prevent dendrites, then dendrite growth is reduced, but the device complexity increases due to multiple solid electrolyte layers

Engineering Contradiction:

Improvedendrite preventionVSAvoidelectrolyte layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A dual-layer solid electrolyte structure is introduced as an intermediary system between the lithium microspheres and the cathode. The first layer (in contact with lithium microspheres) has high conductivity to ensure efficient ion transport, while the second layer provides a controlled interface with the cathode. This intermediary structure manages the complexity by creating distinct functional zones.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The solid electrolyte system uses a composite structure with two different solid electrolyte materials in layers. This composite approach allows each layer to be optimized for its specific function (ion conduction near lithium, interface control near cathode), managing complexity through functional specialization.

Inventive Principle:

Principle #40Composite materials

3Reliability

If a dual-layer solid electrolyte structure is implemented, then dendrite penetration is blocked, but manufacturing complexity increases

Engineering Contradiction:

Improvedendrite penetration resistanceVSAvoidmanufacturing process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Lithium microspheres are pre-formed and pre-coated with solid electrolyte material before being embedded in the oxide-based matrix. This preliminary preparation of the anode structure simplifies the overall manufacturing process by allowing modular assembly, where pre-prepared components are integrated into the final battery structure.

Inventive Principle:

Principle #10Preliminary action

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

Significantly reduces dendrite growth, enhancing battery performance and extending its lifespan by distributing lithium deposition uniformly and creating a barrier against dendrite penetration.

Implementation Method 1

individual microspheres having a first solid electrolyte interface

Methodology Applied

Scientific EffectSolid electrolyte interface formation:

Implementation Method 2

a first solid electrolyte layer comprising a sulfide-based solid electrolyte, the first electrolyte layer positioned between the cathode and the anode

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS11870054B2Solid-state lithium batteries incorporating lithium microspheres

Publication Date: 2024.01.09 NISSAN MOTOR CO LTD

AI summary

A solid-state battery cell includes a cathode, an anode comprising microspheres of lithium metal embedded in an ion and electron conducting oxide-based material, with individual microspheres having a first solid electrolyte interface, and a first solid electrolyte layer comprising a sulfide-based solid electrolyte, the first electrolyte layer positioned between the cathode and the anode. The solid-state battery can also include a second solid electrolyte layer comprising an oxide-based solid electrolyte between the first solid electrolyte layer and the anode, the second solid electrolyte layer having a lower conductivity than the first solid electrolyte layer, and a second solid electrolyte interface between the first solid electrolyte layer and the second solid electrolyte layer.