Silicon Compound Anode Material with Metal Oxides for Slurry Stability
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Solution Overview
Problem
Lithium-ion secondary batteries using silicon as a negative electrode material face instability in aqueous slurry and reduced cycle characteristics due to the reactivity of silicon with aqueous solvents, leading to poor battery performance and capacity retention.
Innovation Solution
A negative electrode material comprising silicon compound particles with a silicon oxide content of 0.5≤x≤1.6, incorporating Li2SiO3 and Li4SiO4, and metal compound particles such as aluminum, zirconium, and yttrium, which stabilize the slurry and improve charge-discharge characteristics by reacting with Li ions, thereby enhancing battery capacity and cycle stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon is used as a negative electrode active material to improve battery capacity, then the battery capacity increases, but the cycle characteristics deteriorate due to expansion and breakage of the active material
Solution Approach 1:
The invention uses a composite structure where silicon particles are embedded in a metal oxide matrix. The metal oxide component provides structural stability and suppresses expansion during charging-discharging cycles, while the silicon particles provide high capacity. This composite approach resolves the contradiction by combining the high capacity advantage of silicon with the structural stability of metal oxide.
Solution Approach 2:
The metal oxide forms a matrix that acts as a flexible constraint structure around silicon particles. This matrix accommodates the expansion and contraction of silicon during lithium insertion and extraction, preventing particle breakage and maintaining electrode integrity over multiple cycles, thus improving cycle characteristics while preserving capacity.
2Quantity of substance
If silicon is used as a negative electrode active material to improve battery capacity, then the battery capacity increases, but the slurry stability deteriorates due to reactivity with aqueous solvents
Solution Approach 1:
The metal oxide acts as an intermediary barrier between silicon and the aqueous slurry environment. It reduces the direct reactivity of silicon with water and other components in the slurry, stabilizing the suspension during electrode fabrication while allowing silicon to maintain its high capacity functionality in the final battery structure.
3Area of stationary object
If the surface layer of the negative electrode active material breaks to create new surface area, then the reaction area increases, but the electrolyte consumption increases due to decomposition reactions
Solution Approach 1:
The metal oxide matrix provides a pre-formed stable surface that cushions and controls the surface evolution during cycling. Instead of uncontrolled breakage creating excessive reactive surfaces, the matrix regulates surface area development, maintaining sufficient reaction area while preventing excessive electrolyte decomposition and consumption.
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 negative electrode material significantly improves the initial charge-discharge characteristics and cycle stability of lithium-ion secondary batteries by stabilizing the slurry and reducing irreversible capacity, leading to enhanced battery performance and capacity retention.
Implementation Method 1
a negative electrode active material particle; the negative electrode active material particle comprising a silicon compound particle containing a silicon compound (SiOx: 0.5≤x≤1.6)
Implementation Method 2
the negative electrode material further comprises at least one of a metal compound particle containing a metal compound and an aggregate of the metal compound particle
Implementation Method 3
capable of stabilizing a slurry prepared in production of a negative electrode for a secondary battery, and capable of improving initial charge-discharge characteristics and cycle characteristics
Data Source
AI summary
A negative electrode material containing a negative electrode active material particle which includes a silicon compound particle containing a silicon compound (SiOx: 0.5≤x≤1.6). The silicon compound particle contains at least one or more of Li2SiO3 and Li4SiO4, and the negative electrode material further contains at least one of a metal compound particle containing a metal compound and an aggregate of the metal compound particle. The negative electrode material is capable of stabilizing a slurry prepared in production of a negative electrode for a secondary battery, and improving initial charge-discharge characteristics and cycle characteristics when it is used as a negative electrode active material for a secondary battery.