NASICON Solid Electrolyte Composition for Safer High-Capacity Batteries
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Solution Overview
Problem
Lithium-ion batteries face irreversible capacity loss due to the formation of a passivation film on the anode during the first charge, leading to reduced capacity and safety concerns associated with liquid electrolytes, which motivates the need for a solid-state battery with high charge and discharge capacity and energy density.
Innovation Solution
A lithium-based solid electrolyte material with a NASICON-type crystal structure, comprising Li3+xAxB2−xSi2PO12−dCd, where A is a trivalent metal, B is a transition metal, and C is a halogen or sulfur, combined with a polymer solid electrolyte and an inorganic salt, to enhance cyclability and cycle life in solid-state batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid electrolyte is used in lithium-ion batteries, then high charge and discharge capacity can be achieved, but safety concerns and thermal runaway issues occur
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid by using a glassy solid electrolyte material. This parameter change (phase transition) eliminates safety concerns and thermal runaway issues associated with liquid electrolytes while maintaining high ionic conductivity for achieving high charge and discharge capacity
Solution Approach 2:
The patent employs a composite solid electrolyte material comprising a glassy matrix formed from multiple oxide components (Li2O-SiO2-P2O5-B2O3-Al2O3-TiO2 system). This composite structure combines the advantages of different materials to achieve both high ionic conductivity and enhanced safety, resolving the contradiction between capacity and reliability
2Reliability
If solid electrolyte is used to improve safety, then safety concerns are addressed, but discharge capacity decreases compared to liquid electrolyte
Solution Approach 1:
The patent optimizes the chemical composition parameters of the glassy solid electrolyte within specific ranges (Li2O: 20-40 wt%, SiO2: 30-50 wt%, P2O5: 10-20 wt%, B2O3: 5-15 wt%, Al2O3: 5-15 wt%, TiO2: 2-10 wt%) to achieve high ionic conductivity while maintaining safety. This parameter optimization enables the solid electrolyte to deliver high discharge capacity comparable to liquid electrolytes
Solution Approach 2:
The patent utilizes the glassy (amorphous) phase of the electrolyte material, which exhibits high ionic conductivity due to its disordered structure that facilitates ion transport. This phase transition from crystalline to glassy state enables the solid electrolyte to achieve high discharge capacity while maintaining the safety advantages of solid-state operation
3Productivity
If graphite anode is used in lithium-ion cell, then high specific capacity can be achieved, but irreversible capacity loss occurs due to SEI formation
Solution Approach 1:
The patent applies preliminary anti-action by using a glassy solid electrolyte that inherently prevents excessive SEI formation on the graphite anode. The solid electrolyte's stable interface and controlled ion transport properties prevent the uncontrolled lithium consumption that occurs with liquid electrolytes, thereby reducing irreversible capacity loss while maintaining high specific capacity
Solution Approach 2:
The patent changes the electrolyte interface properties by transitioning from liquid to solid state, which fundamentally alters the SEI formation mechanism. The glassy solid electrolyte forms a more stable and controllable interface with the graphite anode, reducing lithium consumption during SEI formation and improving overall cell capacity retention
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 proposed solid electrolyte material achieves improved cyclability and increased cycle life, maintaining high charge and discharge capacity while addressing safety concerns related to liquid electrolytes, with ionic conductivity in the range of 10−3 S/cm to 10−5 S/cm.
Implementation Method 1
Batteries including solid electrolytes or hybrid solid electrolytes... ionic conductivity in the range of 10−3 S/cm to 10−5 S/cm
Data Source
AI summary
The present invention provides a solid electrolyte material which may be used in solid-state batteries including semi-solid flow batteries. The resulting solid-state battery may have improved cyclability and increased cycle life. The lithium-based solid electrolyte material may comprise a lithium-based solid electrolyte material comprising Li3+xAxB2−xSi2PO12−dCd wherein A is a trivalent metal, B is a transition metal, C is a halogen or sulfur, x is 0.01 to 0.5, and d is 0 to 12.In an alternate embodiment, the present invention provides a hybrid solid electrolyte comprising the lithium-based solid electrolyte material comprising Li3+xAxB2−xSi2PO12−dCd wherein A is a trivalent metal, B is a transition metal, C is a halogen or sulfur, x is 0.01 to 0.5, and d is 0 to 12, a polymer solid electrolyte and an inorganic salt.