LDH Separator Porosity Gradient Against Zinc Dendrite Short Circuits

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Solution Overview

Problem

Secondary zinc batteries suffer from short circuits due to metallic zinc dendrites that penetrate through conventional LDH separators, leading to reduced service life.

Innovation Solution

An LDH-like compound separator is used, featuring a porous polymeric substrate with plugged pores, where the central region has a lower mean porosity than the peripheral regions, enhancing alkali resistance and effectively preventing zinc dendrite penetration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional LDH separators are used, then hydroxide ion permeability is maintained, but zinc dendrites penetrate through the separator causing short circuits

Engineering Contradiction:

Improveshort circuit preventionVSAvoidzinc dendrite penetration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The separator employs a gradient pore structure where the central region has lower porosity (more dense) than the peripheral regions. This local variation in pore density creates a barrier that prevents zinc dendrites from penetrating through the separator while maintaining hydroxide ion permeability. The denser central region specifically addresses the harmful effect of dendrite penetration without compromising the overall ion conductivity of the separator.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The separator is constructed as a composite material combining polymeric substrate with plugged pores, creating a multi-phase structure that integrates the flexibility and strength of polymers with the protective barrier properties of the plugged pore structure. This composite approach enables simultaneous achievement of mechanical integrity and dendrite blocking functionality.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the separator is made denser to block dendrites, then short circuit prevention improves, but ion conductivity may deteriorate

Engineering Contradiction:

Improveshort circuit preventionVSAvoidion conductivity

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The gradient pore structure allows different regions of the separator to serve different functions: the peripheral regions maintain higher porosity for optimal ion conductivity, while the central region has lower porosity for effective dendrite blocking. This spatial differentiation resolves the contradiction between density requirements for safety and porosity requirements for ion transport.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention addresses the density-conductivity trade-off by introducing a spatial dimension to the pore structure. Instead of uniform density, the porosity varies along the thickness direction, creating a three-dimensional gradient structure that optimizes both protection and conductivity simultaneously through dimensional differentiation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If the separator structure is modified to plug pores centrally, then dendrite resistance improves, but manufacturing complexity increases

Engineering Contradiction:

Improvedendrite resistanceVSAvoidseparator structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The gradient pore structure creates a localized functional region in the center of the separator that specifically addresses dendrite resistance. This localized modification is more efficient than uniformly complex structures, as it concentrates the protective function where it is most needed while keeping other regions simpler for ion transport.

Inventive Principle:

Principle #3Local quality

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 LDH-like compound separator effectively suppresses short circuits by balancing flexibility and strength, ensuring high ion conductivity and preventing zinc dendrite propagation, while maintaining hydroxide ion permeability.

Implementation Method 1

layered double hydroxide (LDH) separators that selectively permeate hydroxide ions while blocking the penetration of zinc dendrites

Methodology Applied

Scientific EffectIon selective permeation: Semipermeable Membrane

Implementation Method 2

an LDH-like compound separator including a porous substrate made of a polymeric material; and a layered double hydroxide (LDH)-like compound with which pores of the porous substrate are plugged

Methodology Applied

Scientific EffectPorosity: Porosity

Data Source

PatentUS12519112B2LDH-like compound separator and zinc secondary battery

Publication Date: 2026.01.06 NGK INSULATORS LTD

AI summary

Provided is an LDH-like compound separator including a porous substrate made of a polymeric material; and a layered double hydroxide (LDH)-like compound with which pores of the porous substrate are plugged. A central region along the thickness of the LDH-like compound separator has a lower mean porosity than peripheral regions along the thickness of the LDH-like compound separator.