Metal Cyanometallate Synthesis via Segmented Aging Reactors
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Solution Overview
Problem
Current sodium/potassium-ion batteries face challenges in mimicking lithium-ion battery structures due to the larger size of sodium/potassium ions, which distorts the material structures, and existing transition metal cyanometallate materials have limitations in capacity and energy density, especially with aqueous electrolytes.
Innovation Solution
A continuous process for synthesizing metal cyanometallate particles with controlled aging kettles to increase particle size and modify morphology, allowing for larger MCM particle sizes and improved properties, enabling their use in large-scale electrochemical storage devices with non-aqueous electrolytes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional synthesis methods are used, then production cost is reduced, but particle size remains small and capacity is limited
Solution Approach 1:
The synthesis process is divided into multiple sequential stages: initial precipitation in a first reactor, followed by aging in separate second and third reactors. This segmentation allows each stage to be optimized independently - the first reactor produces fine particles efficiently, while the subsequent aging reactors progressively grow particle size without requiring complete redesign of the entire synthesis process.
Solution Approach 2:
The aging reactors perform preliminary particle growth action before final product collection. By conducting controlled aging processes in dedicated reactors with specific temperature and time parameters, the particles are pre-grown to optimal sizes before being transferred to the next stage, ensuring that final product meets size specifications without excessive manufacturing complexity.
2Use of energy by moving object
If aqueous electrolytes are used, then cost is reduced, but energy density is limited due to water electrochemical window
Solution Approach 1:
The patent changes the fundamental parameter of electrolyte composition from aqueous to non-aqueous systems. This parameter change expands the electrochemical window beyond water's limitations, enabling higher operating voltages and energy densities. The non-aqueous electrolytes allow the cyanometallate materials to operate at potentials that would cause water decomposition, thereby achieving superior energy storage performance.
3Reliability
If lithium-ion battery structures are mimicked, then performance is optimized, but material distortion occurs due to larger sodium/potassium ion sizes
Solution Approach 1:
The patent applies local quality by creating specific structural features within the cyanometallate materials - open framework structures with enlarged interstitial spaces and tailored pore sizes. These local structural modifications in specific regions of the material accommodate the larger sodium and potassium ions without compromising the overall structural stability, allowing ions to move freely while maintaining framework integrity.
Solution Approach 2:
The invention uses composite cyanometallate materials with specific compositions - combining transition metals (Fe, Mn, Co, Ni, Cu, Zn) with cyanide bridges in controlled ratios. This composite structure creates a hybrid framework that provides both the structural stability needed for material integrity and the flexible interstitial spaces required for larger ion accommodation, resolving the contradiction between performance optimization and structural stability.
4Quantity of substance
If particle size is increased for better performance, then capacity improves, but synthesis complexity increases
Solution Approach 1:
The synthesis process employs continuous useful action through the aging reactors, where particles undergo progressive growth over extended periods (1-24 hours) under controlled conditions. This continuous aging process transforms fine particles from the initial precipitation stage into larger, performance-optimized particles without interrupting the synthesis flow, achieving particle size enhancement as an inherent result of the continuous process rather than through complex post-processing.
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 process enhances the capacity and energy density of sodium/potassium-ion batteries by producing larger MCM particles that can operate effectively in non-aqueous electrolytes, reducing costs and enabling mass production.
Implementation Method 1
In response to stirring the first and second precursors in the main reactor, MCM particles are formed in solution
Implementation Method 2
The process transfers the MCM particles in solution to a secondary reactor, and in response to aging in the secondary reactor, the size of the MCM particles is grown
Implementation Method 3
In response to stirring the first and second precursors in the main reactor, MCM particles are formed
Data Source
AI summary
A system and method are presented for the large scale synthesis of metal cyanometallates (MCMs). First and second precursor solutions are added to a main reactor, where the first precursor includes M1 metal cations. The second precursor solution includes AX′M2(CN)Z′, where M1 and M2 are from a first group of metals and A is from a second group of metals including alkali or alkaline earth metals. In response to stirring the first and second precursors, MCM particles are formed with the formula AXM1NM2M(CN)Z.d[H2O]ZEO.e[H2O]BND, in solution. In response to aging in the secondary reactor, the size of the MCM particles is increases. The aged MCM particles in solution are then transferred to a separation tank, where the aged MCM particles are filtered from the solution and collected. The solution reclaimed from the separation tank back is added back into the main reactor.