Nitrogen-Substituted Silicon Clathrates for Stable Energy Storage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The synthesis of stable carbon and silicon clathrate compounds with high energy of formation has been challenging due to their metastable phases under high pressures, and existing methods have not successfully produced Type I and Type II carbon clathrates with guest atoms inserted into their cage structures.
Innovation Solution
The introduction of nitrogen substitution into carbon and silicon frameworks to form NyC46−y, NySi46−y, and NyCzSi46−y−z clathrate compounds, which reduces the energy of formation and stabilizes the structures by incorporating guest atoms such as Li, Na, and Ba, allowing for the creation of stable nitrogen-substituted carbon and silicon clathrates with tunable electronic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If high pressure synthesis is used to create carbon and silicon clathrates, then the cage structure can be formed, but the compounds remain metastable with high energy of formation
Solution Approach 1:
The patent substitutes framework atoms (carbon or silicon) with nitrogen atoms to change the chemical composition parameters of the clathrate structure. This substitution reduces the energy of formation from positive (metastable) to negative (stable) values, thereby stabilizing the cage structure without requiring continuous high pressure conditions
Solution Approach 2:
The patent creates composite clathrate structures by incorporating guest atoms (such as Li, Na, Ba) within the cage structures formed by nitrogen-substituted carbon or silicon frameworks. This composite approach further stabilizes the structure and enables tuning of electronic properties while maintaining structural integrity at ambient conditions
2Stability of the object's composition
If nitrogen substitution is introduced to stabilize the clathrate structure, then the energy of formation decreases, but the synthesis complexity increases
Solution Approach 1:
The patent employs preliminary action by using arc-melting synthesis to pre-form the nitrogen-substituted clathrate structure in a single high-energy step. This preliminary formation creates a stable framework that can then be processed further, simplifying subsequent synthesis steps compared to gradual assembly methods
Solution Approach 2:
The patent utilizes phase transitions during arc-melting synthesis, where rapid heating and cooling create the desired clathrate structure from molten precursors. This phase transition approach simplifies the synthesis by achieving structural formation through thermal processing rather than complex chemical assembly
3Stability of the object's composition
If guest atoms are inserted into the cage structure to stabilize the clathrate, then the structural integrity improves, but the manufacturing process becomes more difficult
Solution Approach 1:
The patent merges the formation of the cage structure and the incorporation of guest atoms into a single synthesis step using arc-melting. By combining these operations simultaneously rather than sequentially, the patent avoids the difficulty of post-synthesis guest atom insertion while maintaining structural integrity
Data Source
AI summary
Compositions comprising Type I clathrates of silicon (Si46) or carbon (C46) wherein the framework of the cage structure includes nitrogen and carbon or nitrogen and silicon or nitrogen-silicon-carbon atom type composition, with or without guest atoms in their respective cage structures. The clathrate structures are particularly useful for energy storage applications such as battery electrodes.