Zinc Secondary Battery Negative Electrode Polymer Coating

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Zinc secondary batteries face shortened cycle life due to morphological changes of the negative electrode active material, leading to increased resistance and difficulty in charge and discharge processes, as zinc precipitates and accumulates, causing clogging and uneven usage of active material.

Innovation Solution

Incorporating a nonionic water-absorbing polymer with ZnO and Zn particles in the negative electrode, allowing the polymer to adjust its water absorption based on pH variations, facilitating consistent charging and discharging reactions and preventing deterioration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If zinc is used as negative electrode active material, then high capacity is achieved, but morphological changes occur during charge/discharge cycles leading to shortened battery life

Engineering Contradiction:

ImprovecapacityVSAvoidbattery life

Core Design Contradiction:

Quantity of substanceVSDuration of action of stationary object

Solution Approach 1:

A polymer coating layer is applied to the zinc particles surface to act as an intermediary between the zinc and the electrolyte. This coating prevents direct contact and harmful interactions while allowing ionic transport, thereby maintaining high capacity while preventing morphological degradation and extending battery cycle life.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The negative electrode is designed as a composite structure combining zinc particles with a polymer coating material. This composite approach leverages the high capacity of zinc while the polymer component provides structural stability and prevents degradation, resolving the contradiction between capacity and cycle life.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If zinc precipitates from negative electrode during charging, then charge capacity is achieved, but dendrite formation occurs penetrating separator and causing short-circuiting

Engineering Contradiction:

Improvecharge capacityVSAvoiddendrite penetration and short-circuiting

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The polymer coating serves as a mediator that controls zinc precipitation during charging. It guides uniform deposit formation while preventing dendritic growth, allowing charge capacity to be achieved without the harmful short-circuiting effects of dendrite penetration through the separator.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The polymer coating modifies the local physical and chemical parameters at the zinc surface, creating conditions that favor uniform zinc deposition rather than dendritic growth. This changes the precipitation behavior from harmful dendrites to beneficial uniform deposits that maintain safety while enabling charging.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If zinc repeatedly dissolves and precipitates during charge/discharge, then electrochemical reactions occur, but morphological change causes pore clogging and accumulation of isolated zinc

Engineering Contradiction:

Improveelectrochemical reaction rateVSAvoidelectrode morphology

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The polymer coating acts as a stable intermediary framework that accommodates repeated zinc dissolution and precipitation cycles. It prevents the zinc from directly interacting with and degrading the electrode structure, maintaining porosity and preventing isolation of zinc particles while allowing continuous electrochemical reactions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The polymer coating provides a cushioning protective layer before morphological degradation can occur. This pre-protective structure absorbs and distributes the mechanical and chemical stresses of repeated cycling, preventing pore clogging and maintaining electrode integrity throughout the battery's operational life.

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 use of a nonionic water-absorbing polymer enhances the durability of the negative electrode, prolonging cycle life by ensuring uniform reaction processes and maintaining capacity retention during repeated charge/discharge cycles.

Implementation Method 1

Incorporating a nonionic water-absorbing polymer with ZnO and Zn particles in the negative electrode, allowing the polymer to adjust its water absorption based on pH variations

Methodology Applied

Scientific EffectpH-dependent water absorption: Absorption (physical)

Data Source

PatentUS20230261204A1Negative electrode and zinc secondary battery

Publication Date: 2023.08.17 NGK INSULATORS LTD

AI summary

Provided is a negative electrode for use in a zinc secondary battery, including a negative electrode active material containing ZnO particles and Zn particles, and a nonionic water-absorbing polymer in an amount of 0.01 to 6.0 parts by weight on a solid basis, based on the content of the ZnO particles being 100 parts by weight.