Multilayer Solid Electrolyte for Dendrite-Resistant Metal Batteries
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Solution Overview
Problem
Lithium metal batteries face challenges with lithium dendrite formation and propagation across solid electrolytes due to inhomogeneous current density distribution at the Li metal-solid electrolyte interface, leading to short-circuiting and reduced shelf life, despite efforts to improve conductivity and reduce dendrite formation.
Innovation Solution
A multilayer solid electrolyte comprising an ionic conductive and electronically insulating layer paired with an ionic and electronic conductive layer, featuring an ion conductive polymer and a lithium or sodium salt, along with an electronically conductive additive, which acts as a buffer to homogenize current distribution and prevent dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-layer solid electrolyte is used, then the device complexity is low, but lithium dendrite formation occurs due to inhomogeneous current density distribution
Solution Approach 1:
The solid electrolyte is divided into multiple layers with different functional properties. The first layer (in contact with Li metal) has electronic conductivity to homogenize current density, while the second layer has ionic conductivity for efficient ion transport. This segmentation allows each layer to address specific problems: the first layer prevents dendrite formation by uniforming current distribution, and the second layer ensures high ionic conductivity for battery performance.
Solution Approach 2:
Different regions of the electrolyte structure are assigned different material properties tailored to local requirements. The interface with Li metal (first layer) requires electronic conductivity for current homogenization, while the bulk electrolyte (second layer) requires high ionic conductivity for ion transport. This local optimization of material properties resolves the contradiction between simplicity and dendrite resistance.
2Productivity
If high current density is applied to achieve fast charging, then the productivity increases, but lithium dendrite propagation accelerates
Solution Approach 1:
The multilayer electrolyte structure separates the functions of current homogenization and ion transport, enabling the system to handle high current densities without dendrite formation. The first layer's electronic conductivity ensures uniform current distribution even at high rates, while the second layer maintains efficient ion transport, thus allowing fast charging without compromising safety.
3Reliability
If the Li metal-solid electrolyte interface contact is improved, then the current density distribution becomes more homogeneous, but the manufacturing precision requirements increase
Solution Approach 1:
The first electrolyte layer acts as an intermediary between the Li metal anode and the second electrolyte layer. This intermediate layer with electronic conductivity serves as a buffer that homogenizes current density at the interface, compensating for imperfect physical contact between Li metal and the electrolyte. This approach achieves current uniformity without requiring extremely precise manufacturing of the Li metal-electrolyte interface.
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 multilayer electrolyte effectively withstands high current rates without dendrite formation, maintaining discharge capacity and reducing internal resistance, and is expected to enhance performance in both lithium and sodium metal batteries.
Implementation Method 1
an ionic and electronic conductive layer comprising: an ion conductive polymer, at least a lithium or a sodium salt, and an electronically conductive additive
Implementation Method 2
an ionic conductive and electronically insulating layer comprising: an ion conductive polymer, and at least a lithium or a sodium salt
Implementation Method 3
The propagation of lithium across the solid electrolyte may be due to the inhomogeneous electrodeposition of lithium at the Li metal electrode, likely due to presence of uneven current density distribution at the Li metal-solid electrolyte interface
Data Source
AI summary
A multi-layered solid electrolyte for Li- and Na-ion batteries has a dual conductive layer that is an ionic and electronic conductive layer, in combination with an ionic conductive and electronically insulating layer. A process is for preparation of the multi-layered solid electrolyte. A solid-state battery can be prepared with the multi-layered solid electrolyte.