Lithium Potassium Bismuth Oxide Solid Electrolytes for Safe Batteries
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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 are prone to electrochemical degradation when in contact with lithium metal.
Innovation Solution
Development of novel lithium potassium bismuth oxide compounds with specific chemical formulas (I) to (V) that exhibit high lithium ion conductivity, stability, and low activation energy, suitable as solid-state electrolytes or electrode coating layers for lithium ion and metal batteries, utilizing a trigonal crystal structure and aliovalent doping to enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flammable organic solvents are used as electrolyte components, then Li-ion battery performance is improved, but safety risks increase due to flammability
Solution Approach 1:
The patent changes the physical state parameter of the electrolyte from liquid (flammable organic solvent) to solid (oxide compound), eliminating flammability while maintaining ionic conductivity. This parameter change resolves the contradiction by preserving battery performance through high Li-ion conductivity while improving safety by removing the flammable component.
Solution Approach 2:
The patent uses composite oxide materials (e.g., Li3Bi5O12, Li2BiO3) that combine multiple elements to achieve both high ionic conductivity and electrochemical stability. These composite materials replace flammable organic electrolytes while providing the necessary functional properties for battery operation, thus resolving the safety-performance contradiction.
2Reliability
If conventional solid-state lithium ion conductors are used, then safety is improved, but electrochemical stability deteriorates when in contact with lithium metal
Solution Approach 1:
The patent changes the chemical composition parameters of solid-state conductors by using specific oxide compounds (Li3Bi5O12, Li2BiO3) with appropriate crystal structures and stoichiometries. These compositional changes provide both high ionic conductivity and resistance to reduction by lithium metal, resolving the contradiction between safety and electrochemical stability.
Solution Approach 2:
The patent creates an electrochemically inert environment at the lithium metal interface by using oxide compounds that are resistant to reduction. These materials form stable interfaces that prevent degradation reactions, maintaining both safety and electrochemical stability simultaneously.
3Object-affected harmful factors
If existing solid Li-ion conductors are used, then flammability is reduced, but Li+ conductivity and activation energy performance are insufficient
Solution Approach 1:
The patent optimizes the ionic conductivity parameter by selecting oxide compounds with specific crystal structures (spinel for Li3Bi5O12, perovskite for Li2BiO3) that provide efficient Li-ion transport pathways. These structural parameters enable high ionic conductivity (0.1 to 13.0 mS/cm) while maintaining the non-flammable solid-state nature, resolving the contradiction between safety and conductivity performance.
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 lithium potassium bismuth oxide compounds achieve lithium ion conductivities of 0.1 to 13.0 mS/cm at 300K with activation energies between 0.15 to 0.3 eV, providing improved safety and stability for lithium batteries, enabling higher charge/discharge rates and power density.
Implementation Method 1
A primary function of the solid 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 potassium bismuth oxide based compounds are provided which contain an anionic framework capable of conducting lithium ions. Materials of specific formulae are provided and methods to alter the materials with inclusion of aliovalent ions shown. Lithium batteries containing the composite lithium ion electrolytes are provided. Electrodes containing the lithium borate based materials coated on the active material and batteries containing the electrodes are also provided.