Olivine Silicate Cathode Stabilizing Structure for Li-Ion Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion battery cathodes made from Li2MnSiO4 silicate materials abruptly amorphize during charging, leading to gradual performance loss over charge/discharge cycles, necessitating a crystalline silicate material that retains its structure for improved battery reliability.
Innovation Solution
A silicate material with an olivine crystallographic structure, specifically of formula AaZzMnSiO4, where A is an alkali metal, Z is beryllium, magnesium, or calcium, and M is iron, nickel, or manganese, with stoichiometric coefficients that ensure stable insertion and extraction of A during battery cycles, manufactured through processes involving liquid baths and electrochemical reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Li2MnSiO4 silicate material is used for battery cathode, then high theoretical specific capacity is achieved, but crystallographic structure amorphizes during charging leading to performance loss
Solution Approach 1:
The patent modifies the stoichiometric parameters of the Li2MnSiO4 material by introducing substitutions: replacing some Li with alkaline earth metals (Ca, Sr, Ba) and adjusting the Mn content. This changes the crystallographic parameters and bonding characteristics, stabilizing the olivine structure during electrochemical cycling while maintaining high lithium insertion/extraction capacity.
Solution Approach 2:
The invention creates a composite material system by combining multiple elements (Li, Mn, Si, O with substitutions of Ca/Sr/Ba) to form a new compound class with formula Li2-xAaxMn1-yCoySiO4. This composite approach leverages the structural stability of alkaline earth metals and the electrochemical activity of lithium to achieve both structural retention and high capacity.
2Quantity of substance
If Li2MnSiO4 is used as cathode material, then high specific capacity is obtained, but gradual performance degradation occurs over charge/discharge cycles
Solution Approach 1:
By changing the compositional parameters through controlled substitution of Li with Ca/Sr/Ba and adjusting Mn/Co ratios, the patent optimizes the material's electrochemical stability. The modified parameters reduce structural degradation during cycling, extending the operational lifetime while preserving high capacity characteristics.
Solution Approach 2:
The patent applies prior cushioning by pre-modifying the crystal structure with alkaline earth metal substitutions before electrochemical cycling begins. This structural pre-stabilization prevents catastrophic amorphization during initial charging cycles, cushioning against performance degradation and ensuring long-term cycling stability.
3Object-affected harmful factors
If polyanionic silicate material is used, then battery safety is improved by limiting oxygen release, but structural amorphization still occurs during charging
Solution Approach 1:
The patent modifies the chemical composition parameters by introducing alkaline earth metals into the olivine structure, which strengthens the polyanionic framework through enhanced ionic bonding. This compositional adjustment maintains the oxygen-tight structure characteristic of polyanionics while simultaneously preventing charge-induced amorphization.
Solution Approach 2:
By creating a composite olivine structure incorporating both the polyanionic framework (SiO4 tetrahedra) and alkaline earth metal cations, the patent combines the safety benefits of oxygen release prevention with the structural stability needed to maintain crystallinity during electrochemical cycling.
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 olivine structured silicate material maintains its crystallographic structure during battery cycles, enhancing the battery's specific capacity and operational stability, preventing performance degradation and ensuring reliable battery operation.
Implementation Method 1
electrochemically reducing said material of formula (II) in the presence of an element A source electrode under conditions favorable to the formation of the material of formula (I)
Implementation Method 2
obtained by oxidation of a material of olivine crystallographic structure of formula (III)
Implementation Method 3
maintaining a liquid bath comprising, preferably constituted by, the first material in fusion and the second material in the solid state, at a maintenance temperature and for a duration of maintenance in temperature conducive to the insertion of an alkali metal A
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
The present invention relates to a product consisting in whole or in part of a material of olivine crystallographic structure and of formula (I): AaZzMmSiO4 in which A is chosen from lithium (Li), sodium (Na), potassium (K) and mixtures thereof, Z is chosen from beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and mixtures thereof, M is chosen from iron (Fe), nickel (Ni), cobalt (Co), manganese (Mn), chromium (Cr) and mixtures thereof, a, z and m are the stoichiometric coefficients of A, Z and M respectively, and satisfy the following conditions: z > 0, m > 0, a > 0, a + z + m ≤ 2, and 2 ≤ (4 - a - 2z) /m < 4.