Electrode Assembly With Multiple Oxide Layer For Stable Battery Output
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Solution Overview
Problem
All-solid-state lithium batteries in existing technologies do not consistently maintain high output power and capacity over a long period, lacking the desired stability and safety.
Innovation Solution
An electrode assembly comprising a composite body with a transition metal oxide active material, a solid electrolyte with garnet-type crystal structure, and a multiple oxide portion, where the active material is in contact with and covers the multiple oxide portion, enhancing ion and electron conductivity while preventing short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all-solid-state lithium batteries use conventional solid electrolyte materials, then ion conductivity is improved, but output power and capacity stability over time deteriorates
Solution Approach 1:
The patent uses a composite structure consisting of a solid electrolyte layer and a multiple oxide layer (containing at least one of La2Li0.5Co0.5O4, La2Li0.5Ni0.5O4, La2Li0.5Cu0.5O4, La1.5Sr0.5Li0.5Co0.5O4, or Nd2Li0.5Ni0.5O4) formed on the outer surface of the solid electrolyte layer. This composite material approach allows the multiple oxide layer to enhance electron conductivity and structural stability while the solid electrolyte layer maintains ion conductivity, thereby achieving stable output power and capacity over long periods.
Solution Approach 2:
The patent applies different materials with specific properties to different regions: the solid electrolyte layer (e.g., Li7La3Zr2O12 with garnet-type crystal structure) is positioned where high ion conductivity is needed, while the multiple oxide layer is formed on the outer surface where high electron conductivity and structural stability are required. This local optimization of material properties resolves the contradiction between ion conductivity and long-term stability.
2Reliability
If active material directly contacts another electrode, then device complexity is reduced, but safety deteriorates due to short circuit risk
Solution Approach 1:
The multiple oxide layer acts as an intermediary barrier between the active material and the other electrode. This layer prevents direct contact that could cause short circuits while still allowing efficient electron transport due to its high electron conductivity. The solid electrolyte layer serves as another intermediary that separates ionic and electronic conduction paths, further enhancing safety without significantly increasing structural complexity.
3Power
If electron conductivity of active material is increased, then output power is improved, but volume change during charging and discharging increases
Solution Approach 1:
The patent employs a composite structure where the multiple oxide layer (with high electron conductivity) is combined with the active material. This allows the system to achieve high output power through the multiple oxide layer's superior electron conductivity while the active material maintains its structural stability and minimal volume change characteristics during charging and discharging cycles.
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 electrode assembly ensures stable high output power and capacity over time, with improved safety by preventing direct contact between the active material and another electrode, and increased electron conductivity, thus enhancing the performance and lifespan of lithium secondary batteries.
Implementation Method 1
a solid electrolyte having ion conductivity
Implementation Method 2
the electron conductivity of the multiple oxide portion is higher than the electron conductivity of the active material portion
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~4B
AI summary
An electrode assembly includes a composite body which includes an active material layer containing an active material constituted by a transition metal oxide, a solid electrolyte layer (solid electrolyte portion) containing a solid electrolyte, and a multiple oxide molded body (multiple oxide portion) containing at least one of a metal multiple oxide represented by the following general formula (1) : Ln2Li0.5M0.5O4 (wherein Ln represents a lanthanoid, and M represents a transition metal) and a derivative thereof, and a current collector which is provided on one face (one of the faces) of the composite body by being bonded to the active material layer, wherein in the composite body, the multiple oxide molded body, the active material layer, and the solid electrolyte layer are formed in contact with each other in this order from the side of the one face of the composite body.