Phosphate Additive for 5V Manganese Cathode Stability

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Solution Overview

Problem

Lithium ion batteries with 5 V stabilized manganese cathodes face suboptimal cycling performance at high temperatures due to lattice strain and corrosion reactions in conventional carbonate electrolytes, limiting their energy and power density.

Innovation Solution

A lithium ion battery design incorporating a stabilized manganese cathode, a nonaqueous electrolyte composition with a solvent mixture of ethylene carbonate, a co-solvent, and a phosphate additive, which provides improved ion conductivity and stability at high temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional carbonate electrolyte is used with 5V stabilized manganese cathode, then ion conductivity is achieved, but cycling performance deteriorates at high temperature due to corrosion reactions and lattice strain

Engineering Contradiction:

Improvecycling performanceVSAvoidcorrosion reaction

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a film-forming additive as an intermediary substance between the manganese cathode and the carbonate electrolyte. This additive forms a protective interface film that mediates the interaction, preventing direct contact and corrosion reactions between the electrolyte and cathode surface, thereby improving cycling performance at high temperature while maintaining ion conductivity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the electrolyte composition by adding specific additives and adjusting the solvent mixture ratios. These parameter changes alter the chemical properties of the electrolyte to reduce its reactivity with the manganese cathode at high temperatures, suppressing corrosion reactions and improving battery reliability

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If operating voltage is increased to 5V to improve energy density, then energy and power density improve, but corrosion reaction between cathode surface and electrolyte worsens

Engineering Contradiction:

Improveenergy densityVSAvoidcorrosion reaction

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The film-forming additive acts as an intermediary layer at the cathode-electrolyte interface, enabling the battery to operate at 5V by preventing direct corrosion reactions. This mediator allows high voltage operation (improving energy density) while protecting the cathode surface from electrolyte attack

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The additive performs preliminary protective action by forming a stable interface film before significant corrosion can occur. This pre-formed protective layer prevents the harmful corrosion reactions that would otherwise accelerate at 5V operating conditions, enabling sustained high-voltage operation

Inventive Principle:

Principle #9Preliminary anti-action

3Use of energy by moving object

If stabilized manganese cathode is used to achieve 5V operation, then energy density improves, but lattice strain during cycling worsens

Engineering Contradiction:

Improveenergy densityVSAvoidlattice strain

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The protective film formed by the additive acts as a mediator that reduces mechanical stress transmission between the electrolyte and cathode particles during cycling. This intermediary layer helps accommodate lattice strain and prevents structural degradation, maintaining cathode stability during high-voltage operation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The additive provides beforehand cushioning by forming a protective interface that absorbs and mitigates lattice strain during charge-discharge cycles. This pre-established protective layer prevents direct mechanical stress on the cathode structure, reducing degradation from lattice strain while enabling 5V operation

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 enhanced cycling performance and stability at high temperatures, maintaining capacity and reducing lattice strain and corrosion issues, thus improving energy and power density.

Implementation Method 1

the corrosion reaction between the cathode surface and the carbonate electrolyte at the high operating voltage of approximately 5 V

Methodology Applied

Scientific EffectFilm formation: Deposition (physical)

Implementation Method 2

a nonaqueous electrolyte composition providing an ionically conductive pathway between said anode and said cathode

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 3

high-temperature cycling performance still remains a problem due to the intrinsic instability of the traditional carbonate electrolyte and the accelerated decomposition reaction at elevated temperature

Methodology Applied

Scientific EffectThermal stabilization:

Data Source

PatentUS11316201B2Additives to improve electrolyte performance in lithium ion battery

Publication Date: 2022.04.26 SYENSQO SA

AI summary

A lithium ion battery that has a 5 V stabilized manganese cathode and a nonaqueous electrolyte comprising a phosphate additive is described. The lithium ion battery operates with a high voltage cathode (i.e. up to about 5 V) and has improved cycling performance at high temperature.