Silicon Negative Electrode Coating for Lithium Ion Battery Cycle Life
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Solution Overview
Problem
Lithium ion secondary batteries using silicon as a negative electrode active material face early cycle deterioration due to side reactions during charging and discharging.
Innovation Solution
A negative electrode with a coating containing iron (Fe), manganese (Mn), and oxygen (O) is formed on the surface of the silicon-based active material, and a lithium iron manganese-based composite oxide with a layered rock-salt structure is used as the positive electrode active material, along with a specific electrolyte, to improve cyclability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-based negative electrode active material is used, then battery capacity is improved, but cycle life deteriorates due to side reactions
Solution Approach 1:
A coating layer containing iron (Fe), manganese (Mn), and oxygen (O) is formed on the surface of the silicon-based negative electrode active material. This coating acts as an intermediary barrier between the silicon and the electrolyte, suppressing side reactions while allowing lithium ion insertion/extraction, thereby improving cycle life without sacrificing capacity
Solution Approach 2:
The negative electrode is constructed as a composite structure combining silicon-based active material with a metal oxide coating layer. This composite approach leverages the high capacity of silicon while the oxide coating provides structural stability and chemical protection, resolving the contradiction between capacity and cycle life
2Reliability
If coating layer is formed on negative electrode active material layer, then cyclability is improved, but manufacturing complexity increases
Solution Approach 1:
The coating layer is formed in-situ through electrochemical reactions during initial charging cycles, rather than requiring separate coating deposition processes. The iron and manganese ions from the positive electrode migrate and deposit on the negative electrode surface automatically, improving cyclability without adding complex manufacturing steps
Solution Approach 2:
The coating formation occurs during preliminary charging cycles before the battery enters normal operation. This preliminary action prepares the negative electrode surface with a protective layer that suppresses side reactions during subsequent cycling, improving cyclability without affecting normal manufacturing flow
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 significantly enhances the cyclability of the lithium ion secondary battery by suppressing side reactions and maintaining discharge capacity over multiple cycles.
Implementation Method 1
a coating containing iron (Fe), manganese (Mn), and oxygen (O) as constituent elements is formed on a surface of the negative electrode active material layer
Implementation Method 2
a negative electrode active material layer containing a negative electrode active material including silicon (Si) as a constituent element
Data Source
AI summary
A negative electrode for a lithium ion secondary battery, including a negative electrode active material layer containing a negative electrode active material including silicon (Si) as a constituent element, in which a coating including iron (Fe), manganese (Mn) and oxygen (O) as constituent elements is formed on a surface of the negative electrode active material layer.