Silicate Glass Anode Material for Battery Cyclability and Rate Performance
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Solution Overview
Problem
Secondary batteries face limitations in achieving superior charge and discharge characteristics, despite various attempts to improve their performance.
Innovation Solution
An active material comprising lithium, silicon, oxygen, boron, phosphorus, an alkali metal element, a transition element, and an alkaline earth metal element, with specific content ratios, is developed. This material is manufactured through a process involving silicate glass, a carbon source, and lithium doping, resulting in a lithium-containing carbon-reduced silicate glass with distinct XPS and Raman spectral peaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon oxide is used as negative electrode active material with added elements to improve cyclability, then cyclability characteristic is improved, but charge and discharge characteristic remains insufficient
Solution Approach 1:
The invention uses a composite material consisting of silicate glass containing multiple elements (Si, B, P, Li, Na, K, Ca, Mg, Al) in specific ratios. This composite structure provides both improved cyclability through the glass matrix and enhanced charge-discharge characteristics through the specific elemental composition and ratios, particularly with Si content of 60-98 at% and B content of 1-15 at%, which facilitate fast ion transport while maintaining structural stability.
Solution Approach 2:
The invention optimizes the compositional parameters of the silicate glass by controlling the atomic percentages of various elements. Specifically, Si is maintained at 60-98 at%, B at 1-15 at%, and other elements within defined ranges. These parameter changes create a material with optimal balance between cyclability and charge-discharge performance, resolving the contradiction between the two characteristics.
2Quantity of substance
If pyroxene silicic acid compound and reduced tin oxide are used for high-capacity applications, then capacity is improved, but charge and discharge characteristic remains insufficient
Solution Approach 1:
The invention employs a composite silicate glass system that integrates multiple high-capacity elements (Si, Sn, B, P) within a glass matrix. This composite approach achieves high capacity while the glass structure and specific composition (particularly B and P content) facilitate rapid ion transport, thereby improving charge-discharge characteristics simultaneously rather than sacrificing one for the other.
Solution Approach 2:
The silicate glass structure provides local regions with different properties: the SiO2 network provides structural stability and capacity, while B and P atoms create local regions with enhanced ion conductivity. This local quality differentiation allows the material to achieve both high capacity and fast charge-discharge rates by having different regions optimized for different functions.
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 active material enhances the charge and discharge characteristics of secondary batteries by facilitating stable insertion and extraction of electrode reactants, reducing irreversible capacity, and improving electron conductivity.
Implementation Method 1
heating the mixture to thereby form an active material precursor including silicon, oxygen, the first element, the second element, and the third element as constituent elements
Implementation Method 2
mixing the silicate glass with a carbon source to thereby obtain a mixture of the silicate glass and the carbon source; heating the mixture to thereby form an active material precursor
Implementation Method 3
adding lithium electrochemically, chemically, or thermally to the active material precursor to thereby manufacture the active material including lithium
Implementation Method 4
adding lithium electrochemically, chemically, or thermally to the active material precursor
Implementation Method 5
The XPS spectrum of Si2p is measured by X-ray photoelectron spectroscopy (XPS) and defined by a horizontal axis representing a binding energy (eV)
Implementation Method 6
The Raman spectrum is measured by Raman spectroscopy and defined by a horizontal axis representing a Raman shift (cm−1)
Data Source
AI summary
An active material includes lithium, silicon, oxygen, a first element, a second element, and a third element as constituent elements. The first element includes boron, phosphorus, or both. The second element includes at least one of an alkali metal element, a transition element, or a typical element. The alkali metal element excludes lithium. The typical element excludes lithium, silicon, oxygen, boron, phosphorus, the alkali metal element, and an alkaline earth metal element. The third element includes the alkaline earth metal element.