Aqueous Zinc-Ion Battery Electrolyte Additives for Overcharge Stability

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Solution Overview

Problem

Zinc-ion batteries (ZIBs) face safety and reliability issues due to electrolyte decomposition and gas generation during overcharging, leading to battery failure and potential explosion, particularly in neutral electrolytes, which are more severe than in highly acidic or alkaline electrolytes.

Innovation Solution

Incorporation of bromine-based self-sacrificial additives into the electrolyte that undergo oxidation before electrolyte decomposition, providing overcharge protection and maintaining stable electrolyte environments, using cathode materials like Mn2+ expanded hydrated vanadium (MnVO) and manganese dioxide (MnO2).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If neutral electrolytes are used in zinc-ion batteries, then safety advantages are maintained, but gas generation during overcharge becomes more severe compared to highly acidic or alkaline electrolytes

Engineering Contradiction:

ImprovesafetyVSAvoidgas generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A mediator layer comprising manganese dioxide (MnO2) and conductive carbon material is introduced between the zinc anode and neutral electrolyte. This intermediary layer facilitates electron transfer while preventing direct contact between the zinc anode and electrolyte, thereby suppressing water decomposition and gas generation during overcharge while maintaining the safety advantages of neutral electrolytes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a sacrificial protective layer that can be readily replaced. The mediator layer containing MnO2 and conductive carbon material acts as a consumable component that protects the zinc anode during overcharge conditions, allowing for simple replacement rather than complex system redesign.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If overcharge protection is implemented using traditional methods, then battery safety is improved, but battery lifespan and performance stability deteriorate due to electrolyte decomposition and dendrite formation

Engineering Contradiction:

Improveovercharge protectionVSAvoidbattery lifespan

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The mediator layer is pre-formed on the zinc anode surface before battery operation begins. This preliminary protective structure prevents electrolyte decomposition and dendrite formation from the outset, enabling long-term stable operation during overcharge conditions without the need for continuous intervention or system degradation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The mediator layer comprising MnO2 and conductive carbon material provides self-sustaining protection during overcharge. The conductive carbon material maintains electrical conductivity while MnO2 suppresses water decomposition, creating a self-maintaining protective system that extends battery lifespan without requiring external monitoring or adjustment.

Inventive Principle:

Principle #25Self-service

3Quantity of substance

If high capacity cathode materials are used, then energy density is improved, but stability during overcharging deteriorates leading to capacity decay

Engineering Contradiction:

Improveenergy densityVSAvoidcathode material stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The cathode material system is segmented into high-capacity active material particles dispersed within a stable conductive carbon matrix. This segmentation allows the high-capacity material to deliver high energy density while the carbon matrix provides structural stability and maintains integrity during overcharge, preventing capacity decay.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A composite cathode structure is formed by combining high-capacity cathode materials with conductive carbon material. This composite approach enables the system to achieve high energy density from the active material while the carbon component provides structural stability and electrochemical stability during overcharge conditions, preventing capacity decay.

Inventive Principle:

Principle #40Composite materials

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 batteries exhibit significantly prolonged lifespans, with overcharge protection lasting up to 650 hours for Zn∥MnVO and 500 hours for Zn∥MnO2 batteries, maintaining stable electrolyte environments and preventing battery damage.

Implementation Method 1

The self-sacrificial additive undergoes oxidation before electrolyte decomposition, thereby offering protection against overcharging

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

aqueous electrolytes in zinc-ion batteries

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentUS20250219158A1Aqueous zinc-ion battery with stable performance during overcharging

Publication Date: 2025.07.03 CITY UNIVERSITY OF HONG KONG

AI summary

The present invention provides bromine-based additives for overcharge protection in aqueous zinc-ion batteries. These additives undergo oxidation before electrolyte decomposition during overcharging, effectively preventing overcharge. As a result, the batteries demonstrate significantly extended lifespans and maintain stable electrolyte environments. The overcharge protection is effective for more than 650 hours in Zn∥MnO2 batteries and 500 hours in Zn∥MnVO batteries.