Sodium ion secondary battery
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Solution Overview
Problem
Sodium ion batteries with cyclic organic compounds as active materials and non-aqueous electrolytes face capacity retention issues due to dissolution and high interfacial resistance when using oxide or sulfide solid electrolytes.
Innovation Solution
Employing a cyclic organic compound with at least two carbonyl groups bonded via a single bond or conjugated double bond, combined with a complex hydride solid electrolyte containing a Na cation and hydrogen, to reduce interfacial resistance and prevent dissolution, thereby enhancing capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a non-aqueous electrolytic solution is used as electrolyte, then the cyclic organic compound can be dissolved and ions can move freely, but the capacity retention rate decreases when charging and discharging are repeated
Solution Approach 1:
The patent changes the physical state parameter of the electrolyte from liquid (non-aqueous electrolytic solution) to solid (complex hydride). This parameter change resolves the contradiction by maintaining ion conductivity in solid state while preventing the dissolution problem that occurs with liquid electrolytes during repeated charging and discharging cycles
Solution Approach 2:
The patent uses a composite structure where the complex hydride solid electrolyte is combined with specific cyclic organic compounds as active materials. This composite approach enables the solid electrolyte to provide both structural stability for capacity retention and sufficient ion conductivity for operational ease
2Stability of the object's composition
If an oxide solid electrolyte or sulfide solid electrolyte is used, then the electrolyte is solid and stable, but the interfacial resistance between the active material and the solid electrolyte becomes large
Solution Approach 1:
The patent changes the chemical composition parameter of the solid electrolyte from oxide or sulfide-based materials to complex hydride materials. This parameter change reduces the interfacial resistance between the solid electrolyte and cyclic organic compound active materials while maintaining the solid state stability, thereby resolving the contradiction between stability and interfacial resistance
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
This configuration significantly improves capacity retention and reduces interfacial resistance, allowing for more efficient charging and discharging cycles while minimizing the risk of cyclic organic compound dissolution.
Implementation Method 1
a complex hydride as a solid electrolyte, wherein the cyclic organic compound has at least two carbonyl groups —C(═O)—, and the at least two carbonyl groups are bonded via a single bond or at least one conjugated double bond
Implementation Method 2
the cyclic organic compound has at least two carbonyl groups —C(═O)—, and the at least two carbonyl groups are bonded via a single bond or at least one conjugated double bond
Data Source
AI summary
A sodium ion secondary battery includes a cyclic organic compound as an active material and a complex hydride as a solid electrolyte, wherein the cyclic organic compound has at least two carbonyl groups —C(═O)—, the at least two carbonyl groups are bonded via a single bond or at least one conjugated double bond, and the complex hydride includes a Na cation and a complex ion containing H.