Graphene-Coated Bipolar Electrode for Lithium Metal Batteries

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Solution Overview

Problem

Lithium metal batteries face safety concerns due to dendrite formation leading to internal shorting and thermal runaway, and lithium-ion batteries have not yet met cost, safety, and performance targets for high specific energy, energy density, and long cycle life, limiting their commercialization for electric vehicles and microelectronic devices.

Innovation Solution

A bi-polar electrode design featuring a conductive material foil with graphene layers sandwiched between the current collector and the negative or positive electrode layers, enhancing electrical and thermal conductivity, corrosion resistance, and reducing contact resistance, allowing for higher energy density and longer cycle life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If lithium metal is used as the anode to achieve high specific capacity (3,861 mAh/g), then the energy density is significantly improved, but dendrites form during cycling causing internal shorting and thermal runaway

Engineering Contradiction:

Improvespecific capacityVSAvoidcycling stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

A graphene layer is introduced as an intermediary between the lithium metal anode and the electrolyte. This graphene coating acts as a protective barrier that prevents direct contact between lithium and electrolyte, thereby suppressing dendrite formation and improving cycling stability while maintaining the high specific capacity of lithium metal

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The anode is designed as a composite structure combining lithium metal with graphene material. This composite approach leverages the high capacity of lithium metal while utilizing graphene's structural stability and protective properties to prevent dendrite formation, achieving both high energy density and improved reliability

Inventive Principle:

Principle #40Composite materials

2Reliability

If conventional lithium-ion batteries use carbonaceous materials as the anode to improve safety, then cycling stability is improved, but the specific energy and energy density are reduced

Engineering Contradiction:

Improvecycling stabilityVSAvoidspecific energy

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The graphene layer serves as an intermediary protective coating that enables the use of high-capacity lithium metal anodes without suffering from their typical safety issues. This allows the system to achieve both high specific energy (from lithium metal) and good cycling stability (from graphene protection), resolving the trade-off between safety and energy density

Inventive Principle:

Principle #24Intermediary (Mediator)

3Use of energy by moving object

If non-lithiated compounds with high specific capacities are used as the cathode active materials, then the energy density is improved, but the production was stopped due to safety accidents caused by dendrite formation

Engineering Contradiction:

Improvespecific capacityVSAvoidthermal runaway

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The graphene coating is applied preliminarily to the lithium metal anode surface before battery operation. This pre-protective layer prevents dendrite formation and potential thermal runaway events before they can occur, allowing the battery to safely utilize high-capacity cathode materials without the harmful effects that led to production cessation

Inventive Principle:

Principle #9Preliminary anti-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

The bi-polar electrode configuration improves energy density, cycle life, and safety by minimizing non-active materials, reducing internal impedance, and preventing lithium alloying with the current collector, thus addressing the safety and performance limitations of existing lithium-based batteries.

Implementation Method 1

enhancing electrical and thermal conductivity, corrosion resistance, and reducing contact resistance

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

enhancing electrical and thermal conductivity

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

preventing lithium alloying with the current collector

Methodology Applied

Scientific EffectPhysical barrier protection:

Data Source

PatentUS11258070B2Graphene-enabled bi-polar electrode and battery containing same

Publication Date: 2022.02.22 HONEYCOMB BATTERY CO

AI summary

Provided is a bi-polar electrode for a battery, wherein the bi-polar electrode comprises: (a) a current collector comprising a conductive material foil (e.g. metal foil) having a thickness from 10 nm to 100 μm and two opposed, parallel primary surfaces, wherein one or both of the primary surfaces is coated with a layer of graphene material having a thickness from 10 nm to 10 μm; and (b) a negative electrode layer and a positive electrode layer respectively disposed on the two sides of the current collector, each in physical contact with the layer of graphene material or directly with a primary surface of the conductive material foil (if not coated with a graphene material layer). Also provided is a battery comprising multiple (e.g. 2-300) bipolar electrodes internally connected in series. There can be multiple bi-polar electrodes that are connected in parallel.