Carbon-Coated Silicon Oxide Anode for Capacity and Conductivity
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Solution Overview
Problem
Carbon-based negative electrode active materials in lithium secondary batteries have limited theoretical capacity, hindering the development of high-capacity and high-power secondary batteries.
Innovation Solution
A silicon-based oxide particle coated with a carbon coating layer having a surface roughness of 4 nm to 30 nm, combined with a carbon-based active material, to enhance electrical conductivity and stability, is used in the negative electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If carbon-based negative electrode active material is used, then the battery structure is stable, but the theoretical capacity is limited
Solution Approach 1:
The patent uses silicon-based oxide particles coated with carbon coating layer, combined with carbon-based active material to form a composite negative electrode. The silicon-based oxide provides high theoretical capacity (improving quantity of substance) while the carbon coating layer and carbon-based material provide structural stability (maintaining reliability), thus resolving the contradiction between capacity and stability.
2Quantity of substance
If silicon-based oxide particle is used to increase capacity, then the theoretical capacity improves, but the electrical conductivity deteriorates
Solution Approach 1:
The patent introduces a carbon coating layer as an intermediary between the silicon-based oxide particle and the external environment. This carbon coating layer has surface roughness of 4 nm to 30 nm which provides both electrical conductivity (improving reliability) and maintains the high capacity of silicon-based oxide (preserving quantity of substance), thus resolving the contradiction between capacity and conductivity.
3Reliability
If smooth carbon coating layer is applied, then the electrical conductivity improves, but the charge/discharge characteristics deteriorate
Solution Approach 1:
The patent optimizes the surface roughness parameter of the carbon coating layer to a specific range of 4 nm to 30 nm. This parameter change creates an optimal balance where the coating maintains sufficient electrical conductivity while providing adequate surface area and active sites for efficient charge/discharge reactions, thus resolving the contradiction between conductivity and productivity.
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 solution improves discharge capacity, initial efficiency, rate characteristics, and storage capacity of secondary batteries, contributing to higher energy storage and reduced electrical resistance.
Implementation Method 1
the carbon coating layer has a surface roughness of greater than or equal to 4 nm and less than or equal to 30 nm
Implementation Method 2
The silicon-based oxide particle may be doped with at least one metal selected from the group consisting of Mg, Li, Al, Ca, Ti, and V
Implementation Method 3
Secondary batteries convert electrical energy into chemical energy and store the chemical energy so that the secondary batteries can be reused multiple times through charging and discharging
Data Source
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AI summary
The present disclosure relates to a negative electrode active material for a secondary battery, including a silicon-based oxide particle, and a carbon coating layer coating at least a portion of the silicon-based oxide particle, in which the carbon coating layer has a surface roughness of greater than or equal to 4 nm and less than or equal to 30 nm.