LDH Separator Porosity Control for Zinc Dendrite Prevention
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Solution Overview
Problem
Secondary zinc batteries face short circuits due to zinc dendrite penetration through existing separators, which reduces their service life, and current LDH separators only provide limited prevention of this issue.
Innovation Solution
A LDH separator with a porous polymeric substrate densified to a mean porosity of 0.03% to less than 1.0% by plugging pores with a hydroxide-ion conductive layered compound, preventing zinc dendrite intrusion and propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a porous separator is used to allow ion transport, then ion conductivity is improved, but zinc dendrites can penetrate through the separator causing short circuits
Solution Approach 1:
The invention uses a porous substrate as the base structure of the separator to ensure ion conductivity, but then applies LDH coating to modify the pore structure. The porous substrate provides the necessary pathways for ion transport while the LDH coating fills and modifies these pores to prevent dendrite penetration, thus resolving the contradiction between maintaining ion conductivity and preventing short circuits.
Solution Approach 2:
The separator is constructed as a composite material combining a porous substrate with a layered double hydroxide (LDH) coating. This composite structure leverages the advantages of both materials: the porous substrate provides ion transport pathways while the LDH coating provides dendrite-blocking functionality with its dense, tortuous pore structure, effectively resolving the contradiction between ion conductivity and short circuit prevention.
2Reliability
If the separator density is increased to block zinc dendrites, then short circuit prevention is improved, but ion conductivity deteriorates
Solution Approach 1:
The LDH coating is applied locally on the surface and within the pores of the porous substrate, creating a gradient structure where the outer layer is denser for dendrite blocking while the inner porous substrate maintains ion transport pathways. This local differentiation of density allows the separator to simultaneously achieve high dendrite-blocking capability and sufficient ion conductivity.
Solution Approach 2:
The invention utilizes the porous structure of the substrate in combination with LDH coating to create a hierarchical pore system. The coating fills larger pores and creates tortuous pathways that are sufficiently restrictive for dendrites but still permit ion transport, thus resolving the contradiction between density for dendrite blocking and porosity for ion conductivity.
3Reliability
If a dense LDH membrane is formed to block dendrites, then short circuit prevention is improved, but manufacturing complexity increases
Solution Approach 1:
The porous substrate is prepared in advance with controlled pore size and distribution before the LDH coating is applied. This preliminary preparation of the substrate structure simplifies the subsequent coating process and ensures that the LDH coating can effectively fill and modify the pores without requiring complex multi-step manufacturing procedures, thus resolving the contradiction between achieving dense dendrite-blocking structure and maintaining manufacturing simplicity.
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 separator effectively prevents short circuits by significantly reducing porosity and maintaining high ion conductivity, thus enhancing the service life and performance of secondary zinc batteries.
Implementation Method 1
a hydroxide-ion conductive layered compound being a LDH and/or a LDH-like compound with which pores of the porous substrate are plugged
Data Source
AI summary
Provided is a layered double hydroxide (LDH) separator including a porous substrate made of a polymeric material; and a hydroxide-ion conductive layered compound being a LDH and/or a LDH-like compound with which pores of the porous substrate are plugged. The LDH separator has a mean porosity of 0.03% to less than 1.0%.