Lithium Silicate Composite Solid Electrolyte Conductivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Li-ion batteries face safety risks due to flammable organic solvents and stability issues with existing solid-state lithium ion conductors, which limit their use in large-scale energy storage and require materials with high Li+ conductivity, low activation energy, and stability against electrochemical degradation.
Innovation Solution
Development of composite solid-state lithium ion electrolytes with specific chemical formulas, such as Liy(M1)x1Si2-x2(M2)x2O7, Liy(M1)x1Si2-x2Pb1-x3(M3)x3O7, Liy(M1)x1Si2-x2Al1-x3O7, and Liy(M1)x1Si2-x2Be1-x3O7, which exhibit high Li+ conductivity and low activation energy, and are chemically and thermally stable, facilitating their use in all-solid-state batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flammable organic solvents are used as electrolyte components, then Li-ion batteries can achieve good ionic conductivity, but safety risks increase due to flammability
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid by using inorganic solid electrolytes (oxides, sulfides, or phosphates) instead of flammable organic solvents. This parameter change eliminates flammability while maintaining ionic conductivity through careful selection of solid state materials with appropriate crystal structures and ion transport pathways.
Solution Approach 2:
The patent employs composite material systems where inorganic solid electrolytes are combined with specific cathode and anode materials. The electrolyte composition is optimized by selecting from multiple inorganic material classes (oxides like LISICON and NASICON, sulfides like Li3PS4, and phosphates like LiPON) to achieve both high ionic conductivity and electrochemical stability with electrode materials.
2Object-affected harmful factors
If conventional solid Li-ion conductors are used, then safety is improved, but stability against electrochemical degradation deteriorates
Solution Approach 1:
The patent addresses electrochemical stability by carefully selecting inorganic materials with appropriate band gaps and electrochemical windows. Oxide-based electrolytes (LISICON, NASICON, perovskite, garnet) are chosen for their wide electrochemical stability windows, while sulfide and phosphate electrolytes are selected when higher ionic conductivity is needed and electrode materials are carefully matched to prevent degradation.
Solution Approach 2:
The patent introduces protective interface layers and carefully selects electrode materials that act as intermediaries between the solid electrolyte and lithium metal. These interfaces prevent direct contact and electrochemical degradation reactions, allowing the solid electrolyte to maintain both safety and long-term stability.
3Productivity
If high Li+ conductivity is achieved in solid electrolytes, then battery performance improves, but material complexity increases
Solution Approach 1:
The patent achieves high Li+ conductivity in solid electrolytes by optimizing crystal structure parameters, ionic radius ratios, and stoichiometric compositions. Materials are selected and tuned to have open crystal structures with well-defined ion transport pathways, such as the garnet structure for Li7La3Zr2O12 or the LISICON structure for Li14ZnGe4O16, which provide high conductivity without excessive compositional complexity.
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
These composite materials achieve Li+ conductivities of at least 10−5 to 10−6 S/cm at room temperature, with activation energies of 0.4 eV or less, and are stable against lithium metal, enabling safer and more efficient lithium ion batteries with improved mechanical and thermal stability.
Implementation Method 1
A primary function of the solid Li-conductive phase, usually called solid Li-ion conductor or solid state electrolyte, is to conduct Li+ ions from the anode side to the cathode side during discharge and from the cathode side to the anode side during charge
Data Source
AI summary
Solid-state lithium ion electrolytes of lithium silicate based composites are provided which contain an anionic framework capable of conducting lithium ions. An activation energy for lithium ion migration in the solid state lithium ion electrolytes is 0.5 eV or less and room temperature conductivities are greater than 100.5 S/cm. Composites of specific formulae are provided and methods to alter the composite materials with inclusion of aliovalent ions shown. Lithium batteries containing the composite lithium ion electrolytes are also provided.