Solid-State Battery Mg Interlayer for Uniform Lithium Deposition
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Solution Overview
Problem
Secondary batteries with lithium deposition type negative electrodes face issues of high resistance and deteriorated cycle characteristics due to uneven deposition and dissolution of metal lithium, particularly under high current loads.
Innovation Solution
Incorporating a Mg mixture layer between the solid electrolyte layer and the negative electrode current collector, comprising Mg and a second solid electrolyte with a lower Young's modulus than the first solid electrolyte, to facilitate uniform precipitation and dissolution of metal lithium, thereby improving resistivity and cycling properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If metal lithium is deposited between the solid electrolyte layer and the negative electrode current collector, then the negative electrode capacity is improved, but uneven deposition and dissolution occurs leading to high resistance and deteriorated cycle characteristics
Solution Approach 1:
A Mg mixture layer is introduced as an intermediary between the solid electrolyte layer and the negative electrode current collector. This intermediate layer promotes uniform lithium deposition by providing a suitable interface, preventing direct contact between the solid electrolyte and current collector that would cause uneven deposition. The Mg mixture layer acts as a mediator that facilitates consistent lithium insertion and extraction, thereby improving cycle characteristics while maintaining high capacity.
Solution Approach 2:
The composition and structure of the interface between the solid electrolyte and current collector are modified by introducing the Mg mixture layer. This changes the physical and chemical parameters of the deposition interface, creating optimal conditions for uniform lithium deposition. The Mg mixture layer alters the surface energy, conductivity, and mechanical properties at the interface, enabling consistent deposition behavior over many cycles.
2Power
If metal lithium is deposited at high current load, then the power output is improved, but uneven deposition occurs leading to increased resistance
Solution Approach 1:
The Mg mixture layer serves as a mediator that facilitates uniform lithium deposition even under high current loads. By providing a consistent deposition interface, it prevents the formation of lithium dendrites and hot spots that would increase resistance. The intermediate layer ensures that high current density is distributed evenly across the deposition area, maintaining low resistance during high power operation.
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 Mg mixture layer ensures uniform deposition and dissolution of metal lithium, reducing resistance and enhancing cycle characteristics by maintaining a conductive path and suppressing local growth and interfacial delamination.
Implementation Method 1
A Young's modulus of the second solid electrolyte is lower than a Young's modulus of the first solid electrolyte
Data Source
AI summary
The secondary battery includes a positive electrode, a solid electrolyte layer, a negative electrode current collector, and metallic lithium as a negative electrode active material deposited between the solid electrolyte layer and the negative electrode current collector by charging, wherein a Mg mixture layer is present between the solid electrolyte layer and the negative electrode current collector, the solid electrolyte layer includes a first solid electrolyte, Mg mixture layer includes a Mg and a second solid electrolyte, and a Young's modulus of the second solid electrolyte is lower than a Young's modulus of the first solid electrolyte.