Silicon Oxide-Metal Composite Anode for Lithium Battery
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Solution Overview
Problem
Conventional silicon-based negative electrodes for lithium secondary batteries face issues with irreversible capacity due to volume expansion and contraction, leading to reduced lifespan and electrochemical performance.
Innovation Solution
A silicon oxide-metal composite is formed by mixing silicon with a metal oxide and then heating or ball-milling the mixture, which results in a composite with improved mechanical properties and stable cycle characteristics, effectively addressing the volume change issue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon is used as negative electrode material to achieve high capacity, then theoretical capacity increases to about 4200 mAh/g, but volume expansion and contraction occur during charging and discharging leading to electrode destruction and poor contact with current collector
Solution Approach 1:
The patent applies composite materials by combining silicon with metal oxides (such as Co3O4, Mn3O4, Fe3O4, NiO, CuO, ZnO, TiO2, SnO2) to create a composite negative electrode material. This composite structure allows the silicon to provide high lithium storage capacity while the metal oxide components provide structural stability and accommodate volume changes during charging and discharging, preventing electrode destruction and maintaining good contact with the current collector.
2Quantity of substance
If silicon particles are used to achieve high capacity, then lithium storage increases, but irreversible capacity loss occurs due to destruction of electrode containing silicon particles
Solution Approach 1:
The patent uses composite materials combining silicon with metal oxides to create a structure where the metal oxide provides structural stability during cycling. This prevents the destruction of silicon particles that would otherwise occur due to repeated volume expansion and contraction, thereby reducing irreversible capacity loss and extending battery cycle life.
Solution Approach 2:
The patent employs parameter changes by controlling the heating temperature (400-2000°C) and heating time (1-48 hours) to optimize the formation of the silicon-metal oxide composite. These parameter adjustments ensure proper structural development and bonding in the composite material, enhancing its ability to maintain structural integrity during charge-discharge cycles and reduce capacity fading.
3Quantity of substance
If silicon particles are used to achieve high capacity, then lithium storage increases, but poor contact with current collector occurs due to repeated volume expansion and contraction
Solution Approach 1:
The patent applies composite materials by combining silicon with metal oxides to create a composite structure where the metal oxide component provides structural stability and maintains good contact with the current collector. The composite structure accommodates volume changes of silicon during charging and discharging, preventing loss of electrical contact and ensuring reliable electron transport throughout the electrode.
4Reliability
If heating or ball-milling is applied to form silicon oxide-metal composite, then mechanical properties and cycle characteristics improve, but additional processing steps are required
Solution Approach 1:
The patent applies preliminary action by pre-mixing silicon and metal oxide powders in specific ratios before heating or ball-milling. This preliminary mixing ensures uniform distribution of components, which facilitates the formation of a homogeneous composite structure during subsequent processing. This approach improves cycle characteristics while minimizing the complexity of subsequent processing steps.
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 silicon oxide-metal composite enhances the lifespan and electrochemical performance of lithium secondary batteries by suppressing volume expansion during charging and discharging, maintaining discharge capacity over multiple cycles.
Implementation Method 1
heating or ball-milling after mixing silicon and a metal oxide
Implementation Method 2
heating the mixture
Implementation Method 3
heating or ball-milling after mixing silicon and a metal oxide
Data Source
AI summary
A method for preparing a negative electrode active material for a lithium secondary battery according to one aspect of the present invention comprises the steps of: uniformly mixing silicon and metal oxide; and heating or ball-milling the mixture.