Nitrate Salt Cathode Coatings for Stable Lithium Metal Cells

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Solution Overview

Problem

Lithium metal batteries face issues with unreliable performance and premature electrochemical cell failure due to side reactions between metallic lithium and the electrolyte, leading to solid-electrolyte interface formation and electrolyte decomposition.

Innovation Solution

Incorporating a nitrate salt surface coating on electroactive material particles in lithium-ion batteries, specifically using lithium nitrate, cesium nitrate, potassium nitrate, rubidium nitrate, or magnesium nitrate, to reduce side reactions and enhance the stability of the electrochemical cell.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If lithium metal is used in the battery, then the theoretical capacity and electrochemical potential are improved, but side reactions occur between metallic lithium and the electrolyte leading to SEI formation and electrolyte decomposition

Engineering Contradiction:

Improvetheoretical capacityVSAvoidperformance reliability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

A bivalent metal additive (such as calcium, strontium, or barium) is introduced as an intermediary substance in the electrolyte. This additive preferentially reacts with the electrolyte to form a stable interfacial layer that acts as a protective barrier, preventing direct contact and harmful side reactions between the lithium metal and the electrolyte, thereby improving performance reliability while preserving high capacity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The bivalent metal additive performs preliminary protective action by reacting with the electrolyte before lithium metal can cause harmful side reactions. This preliminary reaction forms a stable interface layer in advance, preventing subsequent detrimental interactions and ensuring reliable battery operation from the outset

Inventive Principle:

Principle #10Preliminary action

2Use of energy by moving object

If lithium metal is used in the battery, then the electrochemical potential is improved, but continuous electrolyte decomposition and active lithium consumption occur

Engineering Contradiction:

Improveelectrochemical potentialVSAvoidactive lithium consumption

Core Design Contradiction:

Use of energy by moving objectVSLoss of substance

Solution Approach 1:

The bivalent metal additive serves as a sacrificial intermediary that consumes the electrolyte through controlled reactions, forming a protective layer that prevents uncontrolled continuous decomposition. This intermediary mechanism stops the cycle of active lithium consumption by blocking the pathway for electrolyte breakdown that would otherwise consume lithium

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The potentially harmful reactivity of bivalent metals with the electrolyte is converted into a beneficial protective effect. The controlled reaction of the bivalent metal additive with the electrolyte creates a stable interfacial layer that prevents more harmful continuous decomposition reactions, transforming what could be a detrimental side reaction into a protective mechanism that preserves active lithium

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 nitrate salt coating improves the ionic conductivity and reduces impedance, leading to increased cycle stability and capacity retention of the lithium-ion batteries by minimizing solid-electrolyte interface formation and electrolyte decomposition.

Implementation Method 1

The nitrate salt coating improves the ionic conductivity

Methodology Applied

Scientific EffectIonic conductivity: Conduction (electrical)

Implementation Method 2

The nitrate salt coating improves the ionic conductivity and reduces impedance

Methodology Applied

Scientific EffectImpedance reduction: Electrical Resistance

Data Source

PatentUS20240047673A1Nitrate salt cathode additives and methods of using and forming the same

Publication Date: 2024.02.08 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

The present disclosure provides an electrochemical cell that cycles lithium ions. The electrochemical cell includes a first electrode including a first electroactive material, a second electrode including a second electroactive material, and a separating layer disposed therebetween. The second electroactive material include a plurality of electroactive material particles, where at least a portion of the electroactive material particles have a surface coating that includes a nitrate salt. The first electroactive material can include a lithium metal, and the electrochemical cell can further include a carbonate-based solvent.