LLTO Solid Electrolyte Composite with Glass Phase
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Solution Overview
Problem
Oxide-based lithium lanthanum titanium oxide (LLTO) solid electrolytes face limitations in ionic conductivity due to poor grain boundary conductivity and chemical instability, hindering their practical application in lithium-ion batteries.
Innovation Solution
An inorganic solid electrolyte composite is developed by incorporating a glass material, such as Al2O3 or B2O3, into the LLTO structure, improving both bulk and grain boundary conductivities and chemical stability, with a molar ratio ranging from 1:1 to 1000:1, and employing techniques like tape casting and sintering to form the composite in powder, film, or sheet form.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide-based LLTO solid electrolyte is used, then thermal stability and resistance to moisture are improved, but grain boundary conductivity and chemical stability deteriorate
Solution Approach 1:
The patent creates a composite solid electrolyte system by coating oxide-based LLTO with sulfide-based Li-CSE LGPS. This composite structure combines the thermal stability and moisture resistance of oxides with the high ionic conductivity of sulfides, specifically improving grain boundary conductivity while maintaining the advantages of oxide-based materials.
2Reliability
If sulfide-based Li-CSE is used, then total ionic conductivity is improved, but ease of synthesis deteriorates
Solution Approach 1:
The patent combines sulfide-based Li-CSE LGPS coating with oxide-based LLTO core. The oxide core provides ease of synthesis and moisture resistance, while the sulfide coating layer provides high total ionic conductivity. This composite approach allows the system to achieve superior conductivity without requiring the entire material to be difficult-to-synthesize sulfide.
3Reliability
If LLTO is coated with Li-CSE LGPS, then total ionic conductivity is improved, but manufacturing expense increases
Solution Approach 1:
The patent optimizes the composition parameters of the Li-CSE LGPS coating, specifically using the formula Li3.25Ge0.25P0.75S4 with controlled thickness and composition ratios. By carefully controlling these parameters, the patent achieves high total ionic conductivity (1.62×10−4 S cm−1) while minimizing the amount of expensive coating material required, thus reducing manufacturing expenses.
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 composite exhibits enhanced bulk and grain boundary conductivities, significantly improving the performance of LLTO electrolytes, achieving conductivities of 9.33×10−4 S cm−1 and 2.38×10−5 S cm−1 respectively, and providing improved chemical stability, making them suitable for lithium-ion batteries and other applications.
Implementation Method 1
Lithium-ion conducting solid electrolytes (Li-CSEs)... total ionic conductivity... bulk conductivity σb of 9.33×10−4 S cm−1 and a grain boundary conductivity σgb of about 2.38×10−5 S cm−1
Implementation Method 2
employing techniques like tape casting and sintering to form the composite in powder, film, or sheet form
Data Source
AI summary
An inorganic solid electrolyte glass phase composite is provided comprising a substance of the general formula La2/3-xLi3xTiO3 wherein x ranges from about 0.04 to about 0.17, and a glass material. The glass material is one or more compounds selected from Li2O, Li2S, Li2SO4, Li3PO4, P2O5, P2O3, Al2O3, SiO2, CaO, MgO, BaO, TiO2, GeO2, SiS2, Sb2O3, SnS, TaS2, P2S5, B2S3, and a combination of two or more thereof. A lithium-ion conducting solid electrolyte composite is disclosed comprising a lithium-ion conductive substance of the general formula La2/3-xLi3xTiO3—Z wherein x ranges form about 0.04 to 0.17, and wherein “Z” is the glass material identified above. A battery is disclosed having at least one cathode and anode and an inorganic solid electrolyte glass phase composite as described above disposed on or between at least one of the cathode and the anode.