Oxynitride Solid Electrolyte for High Capacity Batteries
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Solution Overview
Problem
Solid electrolytes in secondary batteries exhibit high ionic resistance and internal resistance, limiting charge/discharge characteristics and practical use, especially with divalent or higher valent metal-containing electrolytes.
Innovation Solution
A solid electrolyte containing an oxynitride with an alkaline-earth metal, phosphorus, and nitrogen is developed, utilizing an atomic layer deposition process to produce a film that enhances ionic conductivity by forming P—N bonds, thereby increasing the theoretical capacity of secondary batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If divalent or higher valent metal-containing solid electrolytes are used, then theoretical capacity increases, but ionic resistance and internal resistance increase
Solution Approach 1:
The patent changes the chemical composition parameters of the solid electrolyte by incorporating specific ratios of divalent metal elements (Mg, Ca, Sr, Ba) and monovalent metal elements (Li, Na, K) along with P, O, and N in controlled proportions. This compositional parameter optimization enables achieving both high theoretical capacity from divalent metals and acceptable ionic conductivity by balancing with monovalent metals and controlling stoichiometry within specific ranges.
Solution Approach 2:
The patent creates a composite solid electrolyte material combining multiple metal elements (divalent and monovalent) with phosphorus, oxygen, and nitrogen in a unified crystalline structure. This composite approach allows the material to simultaneously exhibit high capacity characteristics from divalent metals and improved ionic conductivity from the synergistic combination of elements, resolving the contradiction between capacity and resistance.
2Reliability
If solid electrolyte layer thickness is increased, then battery safety and stability improve, but internal resistance increases and charge/discharge characteristics deteriorate
Solution Approach 1:
The patent optimizes the ionic conductivity parameter of the solid electrolyte material itself through compositional control, achieving sufficiently high bulk ionic conductivity that allows thicker electrolyte layers to be used without excessive resistance penalty. The material's inherent conductivity is enhanced through precise control of metal element ratios and stoichiometry, enabling thickness increases for safety while maintaining acceptable charge/discharge 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 oxynitride film effectively functions as a solid electrolyte, reducing internal resistance and enhancing charge/discharge characteristics, allowing for increased capacity in secondary batteries with divalent metal ions.
Implementation Method 1
utilizing an atomic layer deposition process to produce a film that enhances ionic conductivity by forming P—N bonds
Data Source
AI summary
A solid electrolyte includes an oxynitride that contains an alkaline-earth metal, phosphorus, oxygen, and nitrogen. A P2p spectrum obtained by an X-ray photoelectron spectroscopy measurement of the oxynitride contains a peak component originating from a P—N bond.