Electrolyte Additives for High-Voltage Battery Stability

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Solution Overview

Problem

Current lithium-ion battery electrolyte systems face deficiencies in cycle performance and storage performance, particularly at high voltage and high temperature, due to issues such as gas production and side reactions.

Innovation Solution

Incorporating multi-cyano six-membered N-heterocyclic compounds and unsaturated bond-containing cyclic carbonate compounds as additives in the electrolyte to passivate the positive electrode material surface, inhibit oxidation, and form an anode SEI film, reducing gas production and side reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional electrolyte system with lithium hexafluorophosphate and cyclic/chain carbonates is used, then the battery can operate with basic functionality, but the cycle performance and storage performance deteriorate under high voltage and high temperature conditions

Engineering Contradiction:

Improvecycle performance and storage performanceVSAvoidgas production and side reactions at high voltage and temperature

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a mediating substance (additive containing heterocyclic ring structure with electron-withdrawing groups) that acts as an intermediary between the electrolyte and electrode surfaces. This additive preferentially reacts with the electrode surfaces to form stable protective films, preventing direct harmful interactions between the conventional electrolyte components and electrodes under high voltage and temperature conditions, thereby reducing gas production and side reactions while improving cycle and storage performance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the chemical composition parameters of the electrolyte by adding specific compounds with heterocyclic ring structures and electron-withdrawing groups. This parameter change alters the electrochemical behavior of the electrolyte system, enabling it to form more stable interface films on electrodes under high voltage and temperature conditions, thus improving reliability without sacrificing basic functionality

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the positive electrode material surface remains active, then electrochemical reactions can proceed, but oxidation of the electrolyte occurs and gas production increases

Engineering Contradiction:

Improveelectrochemical reaction activityVSAvoidelectrolyte oxidation and gas production

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality modification by creating a localized protective film on the positive electrode material surface through the addition of heterocyclic compounds. This film selectively covers reactive surface sites, reducing electrolyte oxidation and gas production in those specific areas, while leaving sufficient reactive areas intact to maintain necessary electrochemical reaction activity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent converts the harmful high surface activity of the positive electrode material into a beneficial effect by guiding it to preferentially react with the added heterocyclic additive rather than the electrolyte. This controlled reaction forms protective films that prevent more harmful oxidation reactions, thus converting the potentially harmful high reactivity into a protective mechanism

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

This approach significantly enhances cycle performance and storage performance at high temperature and high voltage by reducing surface activity and side reactions, leading to improved battery efficiency and longevity.

Implementation Method 1

using a multi-cyano six-membered N-heterocyclic compound and a cyclic carbonate compound together as additives of the electrolyte can effectively inactivate the surface of a positive electrode material, inhibit the positive electrode material to oxidize the electrolyte

Methodology Applied

Scientific EffectPassivation:

Implementation Method 2

an anode SEI film can be formed to avoid a contact between the anode and the electrode, thereby effectively reducing side reactions

Methodology Applied

Scientific EffectSEI film formation:

Data Source

PatentUS11309582B2Electrolyte and electrochemical device

Publication Date: 2022.04.19 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

AI summary

The present disclosure relates to the field of energy storage materials, and particularly, to an electrolyte and an electrochemical device. The electrolyte includes an additive A and an additive B, the additive A is selected from a group consisting of multi-cyano six-membered N-heterocyclic compounds represented by Formula I-1, Formula I-2 and Formula I-3, and combinations thereof, and the additive B is at least one unsaturated bond-containing cyclic carbonate compound. The electrochemical device includes the above electrolyte. The electrolyte of the present disclosure can effectively passivate surface activity of the positive electrode material, inhibit oxidation of the electrolyte, and effectively reduce gas production of the battery, while an anode SEI film can be formed to avoid a contact between the anode and the electrode and thus to effectively reduce side reactions.