Polymer Electrolyte Salt Additive for Stable Lithium Metal Anodes

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Solution Overview

Problem

Existing lithium metal batteries face issues such as dendritic Li formation, uncontrolled interfacial reactions, and large volume variations, leading to low Coulombic efficiency and short cycling lifetime, particularly in solid or semi-solid batteries, necessitating improvements in safety, stability, and performance.

Innovation Solution

An electrolyte product comprising a polymer-based matrix with dispersed electrolyte and additive metal salt compositions forms a mixed metal alloy layer and solid electrolyte interphase (SEI) layer in-situ, enhancing battery performance and safety by mitigating adverse reactions and stabilizing the anode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If lithium metal is used as anode material to achieve high theoretical specific capacity and low reduction voltage, then battery energy density is improved, but dendritic Li formation and uncontrolled interfacial reactions occur leading to low Coulombic efficiency and short cycling lifetime

Engineering Contradiction:

Improvespecific capacityVSAvoidcycling lifetime

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

A dual functional additive salt is introduced as an intermediary substance between the lithium metal anode and the electrolyte. This additive salt contains a first metal salt and a second metal salt that react with lithium to form a mixed metal alloy layer, acting as a protective intermediary layer that prevents direct contact between lithium and electrolyte, thereby reducing dendrite formation and improving cycling lifetime while maintaining high specific capacity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite anode structure by forming a mixed metal alloy layer comprising multiple metal elements (lithium and at least one other metal from the additive salt). This composite material structure provides both the high capacity benefits of lithium metal and the stability advantages of alloy formation, resolving the contradiction between energy density and cycling lifetime

Inventive Principle:

Principle #40Composite materials

2Reliability

If artificial solid electrolyte interphase (SEI) films are designed on Li metal electrode to solve dendrite formation and improve stability, then cycling lifetime is extended, but battery performance in terms of overall capacity and power density may be compromised

Engineering Contradiction:

Improvecycling lifetimeVSAvoidpower density

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent modifies the composition and structure of the SEI layer by incorporating multiple metal elements from the dual functional additive salt. This changes the physical and chemical parameters of the SEI film, creating a more conductive and less resistive interface that allows fast ion transport while maintaining protective functions, thus improving power density without sacrificing cycling lifetime

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If mixed metal layers are provided to reduce Li-metal reactivity or protective SEI layers are provided, then battery safety and stability are improved, but battery performance in terms of overall capacity and power density needs to be maintained

Engineering Contradiction:

Improveanode reactivityVSAvoidoverall capacity

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The dual functional additive salt performs self-service by automatically forming the protective mixed metal alloy layer and modifying the SEI layer through in-situ reactions during battery operation. The additive salt components react with lithium to create the protective structure themselves, reducing the need for external interventions while maintaining both safety and capacity

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The additive salt is pre-introduced into the electrolyte before battery assembly, where it awaits contact with lithium metal. Upon contact, it immediately begins forming the protective mixed metal alloy layer and modifying the SEI, performing preliminary protective action before harmful reactions or dendrite formation can occur, thus preserving both safety and capacity

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

The in-situ formation of a protective hybrid layer improves battery performance by reducing anode reactivity, providing ion conductivity, and stabilizing the anode, thereby extending cycle life and maintaining capacity and power density.

Implementation Method 1

an amount of an additive salt composition configured to, upon partaking in a redox reaction, form a mixed metal alloy layer with the anode metal

Methodology Applied

Scientific EffectRedox reaction: Redox Reactions

Implementation Method 2

form a mixed metal alloy layer with the anode metal and a solid electrolyte interphase (SEI) layer

Methodology Applied

Scientific EffectSEI formation:

Data Source

PatentUS20260074276A1Electrolyte with dual function salt additive

Publication Date: 2026.03.12 LIONVOLT BV

AI summary

The present disclosure relates to an electrolyte product (1), formed as a solid or semi-solid layer, comprising a polymer-based matrix, having dispersed therein an amount of an electrolyte salt composition (4) and an amount of an additive salt composition (5). The disclosure further relates to a method of manufacturing a battery cell product, a battery cell product comprising the electrolyte product, and a battery product comprising a plurality of battery cell products.