Silicate-Silicon Anode Material with Zr Oxides for Cycle Stability
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Solution Overview
Problem
Secondary batteries using silicon particles as negative electrode active materials face deterioration in charge/discharge cyclic characteristics due to large volume changes during charge/discharge reactions, leading to particle structure breakage.
Innovation Solution
A negative electrode active material comprising a silicate phase with Li, Si, and Mx, where Mx is an element other than alkali or alkaline earth metals, with silicon particles dispersed in this phase, and oxide particles such as Zr, Ce, Ca, Al, Fe, Mg, Ti, or W dispersed within, which enhances the hardness and ion conductivity, preventing volume changes and structure breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon particles are used as negative electrode active material, then ion intercalation capacity per unit volume is improved, but charge/discharge cyclic characteristics deteriorate due to volume changes and particle structure breakage
Solution Approach 1:
The patent uses a composite material system consisting of silicon particles dispersed in a silicate phase matrix containing metal oxide particles. The silicate phase acts as a binding matrix that holds the silicon particles together, while the metal oxide particles (such as ZrO2, CeO2, CaO, Al2O3, Fe2O3, MgO, TiO2, or WO3) dispersed within the silicate phase enhance the overall hardness and structural stability of the composite. This composite structure allows silicon to maintain its high ion intercalation capacity while the silicate phase and metal oxide particles work together to prevent particle structure breakage during charge/discharge cycles, thus improving cyclic characteristics.
Solution Approach 2:
The patent applies local quality by creating a heterogeneous composite structure where different components serve specific functions: silicon particles provide high capacity regions for ion intercalation, the silicate phase provides a flexible matrix that accommodates volume changes, and metal oxide particles provide localized hardness enhancement and structural support. This spatial distribution of different material properties throughout the composite allows the material to simultaneously achieve high capacity and good cyclic stability.
2Quantity of substance
If silicon particles undergo charge/discharge reactions, then ion storage capacity is improved, but volume changes cause particle structure breakage
Solution Approach 1:
The silicate phase acts as a flexible shell or matrix surrounding the silicon particles. This silicate phase is capable of accommodating the volume changes that occur during charge/discharge reactions without breaking. The flexible nature of the silicate phase allows it to expand and contract with the silicon particles, maintaining particle structure integrity even as the silicon undergoes significant volume changes during lithium ion insertion and extraction.
Solution Approach 2:
The composite material structure combines silicon particles with a silicate phase matrix containing dispersed metal oxide particles. The silicate phase provides a flexible, accommodating matrix that can handle volume changes, while the metal oxide particles dispersed within provide localized structural support and hardness enhancement. This composite approach allows the material to maintain particle structure integrity while enabling high ion storage capacity through the silicon component.
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 solution effectively prevents deterioration in charge/discharge cyclic characteristics by reducing volume changes and enhancing ion conductivity, leading to improved battery performance and capacity retention.
Implementation Method 1
the silicate phase having a predetermined component and predetermined hardness, and further dispersing predetermined metal oxide particles in the silicate phase can prevent a volume change of the silicon particles due to the charge/discharge reaction
Implementation Method 2
dispersion of silicon particles and predetermined metal oxide particles in a silicate phase having a predetermined component can prevent a volume change of the silicon particles due to the charge/discharge reaction, to thereby prevent the breakage of the particle structure
Implementation Method 3
a silicate phase having a predetermined component and predetermined hardness, and further dispersing predetermined metal oxide particles in the silicate phase
Data Source
AI summary
This negative electrode active material for a secondary cell which is one aspect of the present disclosure comprises: a silicate phase that contains Li, Si, and Mx (Mx alkali metal, alkaline earth metal, and an element other than Si); silicon particles dispersed in the silicate phase; and oxide particles that contain Zr dispersed in the silicate phase. The content of each element with respect to the total of the elements other than oxygen in the silicate phase is 3 to 45 mol % for Li, 40 to 78 mol % for Si, and 1 to 40 mol % for Mx.