Solid-State Battery Alloy Anode for Stable Interfacial Contact
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Solution Overview
Problem
Conventional Li-metal batteries face issues with capacity retention and longevity, especially when operated at higher capacities, due to interfacial resistance and cycling-induced stresses, which affect their performance and lifespan.
Innovation Solution
The use of an alloy anode comprising a first component that forms a solid solution with lithium and a second component that does not, with the first component being present in greater amounts, ensures the anode remains in contact with the solid-state electrolyte during cycling, minimizing interfacial resistance and enhancing capacity retention and longevity. Additionally, a solid-state electrolyte is employed to address safety concerns and improve electrode utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional Li-metal anodes are used, then high energy density is achieved, but capacity retention and longevity deteriorate due to interfacial resistance and cycling-induced stresses
Solution Approach 1:
The patent employs a composite alloy anode structure comprising multiple elements (e.g., Li-Al-Sn, Li-Mg-Sb) where different components serve distinct functions: lithium provides high capacity, aluminum/magnesium form solid solutions to maintain structural integrity, and tin/antimony/sb enhance stability. This composite approach resolves the contradiction by combining materials that individually address different aspects of the energy density vs. reliability trade-off.
Solution Approach 2:
The patent modifies the anode's compositional parameters by introducing specific alloying elements in controlled proportions (e.g., Al: 5-30 atom%, Sn: 2-15 atom%). These parameter changes transform the anode from pure lithium metal to a stabilized alloy composite, thereby improving capacity retention while maintaining high energy density through optimized composition ratios.
2Productivity
If the anode is subjected to charging/discharging-induced stresses, then cycling capacity is improved, but interfacial contact with solid-state electrolyte deteriorates due to volume expansion/contraction
Solution Approach 1:
The patent applies local quality by creating a heterogeneous alloy structure where different regions serve different purposes: lithium-rich zones provide high capacity, while aluminum/magnesium-rich zones provide structural stability and maintain interfacial contact. This local differentiation allows the anode to withstand cycling stresses without losing electrolyte contact.
Solution Approach 2:
The alloying elements (Al, Mg, Sn, Sb) act as pre-configured cushioning components that anticipate and accommodate volume changes during lithium insertion/extraction. These elements form stable solid solutions that buffer the mechanical stresses, preventing anode-electrolyte interface separation before it occurs.
3Reliability
If solid-state electrolyte is used, then safety and energy density are improved, but interfacial resistance increases compared to liquid electrolytes
Solution Approach 1:
The patent modifies the interfacial parameters by introducing alloying elements that change the surface properties of the anode. These compositional changes reduce interfacial resistance between the solid-state electrolyte and anode by creating more compatible interfaces, thereby mitigating the inherent high resistance problem of solid-state systems.
Solution Approach 2:
The alloying elements (particularly Al and Mg) act as intermediary materials that facilitate better interfacial contact between the lithium-based anode and the solid-state electrolyte. These intermediaries reduce the resistance barrier at the interface while maintaining the safety advantages of solid-state electrolytes.
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
This configuration significantly improves capacity retention and longevity of the battery, allowing it to maintain high performance for a longer period, with the alloy anode maintaining contact with the electrolyte even in discharged states and reducing interfacial resistance, while the solid-state electrolyte enhances safety and energy density.
Implementation Method 1
The first component can for a solid solution with a metal and/or metal ion (e.g., Li/Li+) that is transported during cycling of the battery
Implementation Method 2
a solid-state electrolyte... with high ionic conductivity
Implementation Method 3
the first component and the second component may not be transferred during cycling (e.g., charging, discharging)
Data Source
AI summary
Batteries include a cathode, a solid-state electrolyte, and an anode. In aspects, the anode comprises an alloy including from about 50 atom % to about 90 atom % lithium, from about 5 atom % to about 50 atom % of a first component, and from about 0.1 atom % to about 10 atom % of a second component. In aspects, the anode includes from about 20 atom % to about 99 atom % of a first component and from about 1 atom % to about 20 atom % of a second component. The first component is selected from a group consisting of magnesium, silver, and combinations thereof. The second component is selected from a group consisting of calcium, aluminum, gallium, boron, carbon, silicon, tin, zinc, indium, antimony, silver, and combinations thereof. An amount of the first component is greater than an amount of the second component. The solid-state electrolyte is positioned between the cathode and the anode.