Doped Oxide Solid-State Lithium-Ion Conductor for Safer High Conductivity
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Solution Overview
Problem
Current solid-state lithium batteries face challenges with ionic conductivity and safety concerns due to the toxicity and reactivity of sulfide electrolytes, while oxide electrolytes have limited application due to low conductivity and incompatibility with high-voltage cathode materials.
Innovation Solution
A solid-state ion conductor comprising a compound of Formula Li1+(4−a)yAayM1−yXO5, where A is an element from Groups 1 to 3 or 11 to 13, M is from Groups 4 or 14, and X is from Groups 5, 15, or 17, with a dopant that improves lithium conductivity by creating a distorted lithium environment, is used as a solid electrolyte in lithium batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide solid-state electrolytes are used, then lithium conductivity is improved, but toxicity and safety concerns increase due to reaction with air or water to evolve hydrogen sulfide
Solution Approach 1:
The patent changes the chemical composition parameters by doping the oxide electrolyte with specific elements (Al, Ga, In from Group 13; Ti, Zr, Hf from Group 4; P, As from Group 15) to achieve high lithium conductivity (≥10^-6 S/cm at 25°C) while maintaining the stability of oxide materials. This compositional modification allows the oxide electrolyte to reach conductivity levels previously only achievable with sulfides, without the associated toxicity issues.
Solution Approach 2:
The patent creates a composite electrolyte system by combining oxide base materials (such as Li2SiO3, Li2GeO3, Li2SnO3) with multiple dopant elements. This composite approach leverages the stability of oxides while the dopants enhance ionic conductivity, achieving a material that combines the safety advantages of oxides with the high conductivity characteristics of sulfides.
2Object-affected harmful factors
If oxide solid-state electrolytes are used, then toxicity is reduced and stability in air is improved, but lithium conductivity and compatibility with high-voltage cathode materials deteriorate
Solution Approach 1:
The patent modifies the oxide electrolyte composition by introducing dopants that create lithium vacancies and distort the lithium coordination environment. The dopant concentration (x in Li1+xM1-xPO5) is optimized to achieve maximum conductivity enhancement while maintaining structural stability, allowing oxides to reach conductivity levels of ≥10^-6 S/cm at 25°C.
Solution Approach 2:
The dopant elements are strategically introduced at specific lattice positions to create localized lithium vacancy clusters and distort the lithium coordination polyhedra. This local structural modification enhances lithium ion mobility in specific regions of the crystal structure, thereby improving overall ionic conductivity without compromising the bulk stability of the oxide material.
3Stability of the object's composition
If oxide solid-state electrolytes are used, then stability in air is improved, but compatibility with high-voltage cathode materials and lithium metal deteriorates
Solution Approach 1:
The patent adjusts the electrochemical stability window of the oxide electrolyte by optimizing dopant composition and concentration. The dopants modify the band structure and defect chemistry of the oxide, expanding its electrochemical stability range to accommodate high-voltage cathode materials (≥4.3V vs. Li/Li+) and lithium metal anodes, enabling broader adaptability while maintaining air stability.
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 solution achieves high ionic conductivity and stability, allowing for improved performance in lithium batteries, including compatibility with lithium transition metal oxides and lithium metal, while avoiding the safety concerns of sulfides.
Implementation Method 1
Available sulfides can provide greater lithium conductivity than oxides... The solid-state ion conductor can have an ionic conductivity equal to or greater than of 1×10−7 siemens per centimeter (S/cm), at 23° C.
Implementation Method 2
A is an element of Groups 1 to 3 or 11 to 13, or a combination thereof, wherein an oxidation state a of A is 1≤a≤3... a dopant that improves lithium conductivity by creating a distorted lithium environment
Data Source
AI summary
A solid-state ion conductor including a compound of Formula 1:Li1+(4−a)yAayM1−yXO5 Formula 1wherein, in Formula 1, A is an element of Groups 1 to 3 or 11 to 13, or a combination thereof, wherein an oxidation state a of A is 1≤a≤3, M is an element having an oxidation state of +4 of Groups 4 or 14, or a combination thereof, X is an element having an oxidation state of +5 of Groups 5, 15, 17, or a combination thereof, and 0<y≤1.