Solid Composite Electrolyte Membrane for Lithium Batteries
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Solution Overview
Problem
Current lithium ion batteries face limitations due to the electrochemical instability and short life cycle of liquid electrolytes, as well as the poor stability of solid lithium ion conductors, which restrict their high conductivity and compatibility with electrodes.
Innovation Solution
A solid composite electrolyte membrane is developed using a glass-ceramic or polymer-ceramic composite, formed from a mixture of lithium carbonate, alumina, titanium dioxide, and ammonium dihydrogen phosphate, which can be either porous or fully dense and water impermeable, with controlled porosity and conductivity achieved through varying sintering temperatures and times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid electrolytes are used in lithium ion batteries, then high conductivity is achieved, but flammability and corrosiveness severely limit performance
Solution Approach 1:
The patent changes the physical state parameter of the electrolyte from liquid to solid, and modifies the chemical composition parameters by using specific glass-ceramic compositions (containing Li2O, Al2O3, TiO2, P2O5) to achieve both high ionic conductivity and electrochemical stability, eliminating flammability and corrosiveness issues
Solution Approach 2:
The patent employs composite glass-ceramic materials combining multiple oxides (lithium oxide, alumina, titanium dioxide, diphosphorous pentoxide) to create a solid electrolyte that integrates high ionic conductivity with enhanced chemical stability and electrochemical compatibility, resolving the trade-off between conductivity and stability
2Strength
If the membrane is made fully dense, then water impermeability and mechanical strength are improved, but porosity and ease of processing deteriorate
Solution Approach 1:
The patent uses sintering temperature as a control parameter to adjust the degree of densification. By varying the sintering temperature (400-1200°C) and time, the membrane can be produced with controlled porosity (0-50%), allowing optimization between mechanical strength and processing ease for different applications
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 membrane exhibits high room temperature conductivity and enhanced chemical stability, suitable for lithium batteries, with the ability to be either porous or fully dense, addressing the limitations of existing electrolytes and providing mechanical strength and water impermeability.
Implementation Method 1
a lithium ion conducting solid electrolyte membrane comprised of a glass-ceramic or polymer-ceramic composite
Implementation Method 2
The tape is preferably heated at a temperature from about 25 to 400° C. to burn off the organic components
Implementation Method 3
The tape is preferably sintered at a temperature of from 400 to 1200° C. The resulting membrane is a solid glass-ceramic composite membrane
Data Source
AI summary
A solid composite electrolyte membrane for use in a lithium battery is provided which exhibits a conductivity ranging from about 10−4 S cm−1 to about 10−3 S cm−1 at ambient temperature. The membrane is formed by providing a glass or glass-ceramic powder formed from a mixture of lithium carbonate, alumina, titanium dioxide, and ammonium dihydrogen phosphate. The powder is mixed with a conditioning agent and at least one solvent, followed by the addition of a binder and one or more plasticizers. The resulting slurry is cast into a tape which is then subjected to a binder burn-off and sintering process to form the membrane. The resulting membrane may be a glass-ceramic composite having a porosity ranging from 0 to 50%, or the membrane may be further infiltrated with a polymer to form a water-impermeable polymeric-ceramic composite membrane.