Oxide Solid Electrolyte Composition for Low-Temperature Sintering
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Solution Overview
Problem
Current lithium batteries face safety issues due to liquid electrolytes, and solid electrolytes like polymer, sulfide, and oxide electrolytes have limitations such as thermal instability, reactivity, and low ionic conductivity, leading to reduced battery performance.
Innovation Solution
A solid electrolyte composed of LiaBbAlmQnOcXd, where Q has a different ionic radius and valence states than Al, is manufactured through mechanical milling and heat treatment, achieving high density and ionic conductivity at low sintering temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If oxide solid electrolytes are used, then thermal stability is improved, but sintering temperature becomes too high and ionic conductivity is low
Solution Approach 1:
The patent changes the chemical composition parameters of the solid electrolyte by incorporating specific metal elements (Mg, Ca, Sr, Ba, Zn, Mn, Fe, Co, Ni, Cu, or their alloys) in controlled amounts (0.1-5 wt%) into the oxide matrix. This compositional parameter change enables the material to achieve high ionic conductivity and thermal stability at lower sintering temperatures (900-1100°C) compared to conventional oxide electrolytes that require 1200-1400°C
Solution Approach 2:
The patent creates a composite oxide solid electrolyte system by combining base oxide materials (such as Li2SiO3, Li2GeO3, Li2SnO3, Li2TiO3, Li2ZrO3, Li2WO4, Li2MoO4, Li2SeO3, Li2TeO3, Li2GeSeO3, Li2GeTeO3, Li2SiSeO3, or Li2SiTeO3) with dopant metal elements. This composite structure synergistically improves ionic conductivity and thermal stability while reducing the required sintering temperature
2Reliability
If sulfide solid electrolytes are used, then ionic conductivity is improved, but reactivity with air and cathode materials increases
Solution Approach 1:
The patent modifies the chemical composition by incorporating specific metal dopants (Mg, Ca, Sr, Ba, Zn, Mn, Fe, Co, Ni, Cu, or their alloys) at controlled concentrations (0.1-5 wt%) into the oxide electrolyte matrix. This compositional adjustment optimizes the material's chemical stability to reduce reactivity with air and cathode materials while preserving high ionic conductivity
Solution Approach 2:
The patent converts the potential harm of high reactivity into a benefit by carefully selecting and controlling the type and amount of metal dopants. The dopants modify the surface chemistry and electronic structure of the oxide electrolyte, creating a more stable interface with cathode materials and reducing unwanted side reactions, while the underlying high ionic conductivity of the oxide matrix is maintained
3Reliability
If polymer solid electrolytes are used, then safety is improved, but thermal stability deteriorates
Solution Approach 1:
The patent employs composite oxide solid electrolyte materials that combine the safety benefits of solid electrolytes with the thermal stability of inorganic oxide matrices. The composite structure of base oxides (such as Li2SiO3, Li2GeO3, Li2SnO3, Li2TiO3, Li2ZrO3, Li2WO4, Li2MoO4, Li2SeO3, Li2TeO3, Li2GeSeO3, Li2GeTeO3, Li2SiSeO3, or Li2SiTeO3) doped with metal elements provides both safety and high thermal stability, overcoming the thermal degradation issues of polymer electrolytes
4Reliability
If solid electrolyte density is increased, then ionic conductivity is improved, but adhesion with electrode materials deteriorates
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: the density of the solid electrolyte (controlled through compositional ratios and sintering conditions), the type and concentration of metal dopants (0.1-5 wt%), and the sintering temperature (900-1100°C). These parameter changes create an optimal balance where the solid electrolyte achieves sufficient density for high ionic conductivity while maintaining adequate surface characteristics and mechanical properties for good adhesion with electrode materials
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 new solid electrolyte provides improved ionic conductivity and adhesion with electrode materials, enhancing battery performance and safety.
Implementation Method 1
heat treating the glassy solid ion conductor at a temperature equal to or greater than an initial thermal decomposition temperature (Ts) as measured by differential scanning calorimeter (DSC) to provide a crystal-containing solid ion conductor
Implementation Method 2
mechanically milling a lithium source, a boron source, an aluminum source, a Q element source, and a halogen source to provide a glassy solid ion conductor
Implementation Method 3
initial thermal decomposition temperature (Ts) as measured by differential scanning calorimeter (DSC)
Data Source
AI summary
A solid electrolyte, a method of manufacturing the same, and a lithium battery including the solid electrolyte. The solid electrolyte may include a solid ion conductor represented by Formula 1:LiaBbAlmQnOcXd Formula 1wherein, in Formula 1, Q is an element that has an ionic radius that differs from an ionic radius of Al by less than 30% and has +3 and +5 valence states, X is at least one of F, Cl, Br, or I, 3.5≤a≤4.5, 3≤b<5.2, 1≤m≤3, 0<n<2, 11≤c≤13, and 0<d≤1.5.