Composite-Coated Nano-Tin Anode for Lithium-Ion Batteries
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Solution Overview
Problem
Tin-based negative electrode materials for lithium-ion batteries face issues with pulverization and the formation of unstable Solid Electrolyte Interphase (SEI) during lithium intercalation/deintercalation, leading to poor cycle life and conductivity problems.
Innovation Solution
A composite-coated nano-tin negative electrode material is developed, featuring a tin-based nanomaterial with a nano-copper layer and a conductive protective carbon layer, where the carbon layer is between the tin-based nanomaterial and the nano-copper layer, to alleviate volume expansion and enhance conductivity, preventing direct contact with the electrolyte and oxidation of copper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If tin-based materials are used as negative electrode material, then capacity is improved, but volume changes during lithium intercalation/deintercalation cause pulverization and poor cycle life
Solution Approach 1:
The patent applies nested doll principle by creating a multi-layer coating structure where an inner carbon layer is embedded within an outer copper layer, both surrounding the tin-based nanomaterial core. This nested structure allows the tin to undergo volume changes during lithium intercalation while being constrained and protected by the concentric coating layers, preventing pulverization and maintaining structural integrity for improved cycle life.
Solution Approach 2:
The patent uses composite materials principle by combining tin-based nanomaterial with carbon and copper coating layers to create a composite structured negative electrode material. The carbon-copper composite coating provides mechanical strength and structural stability to accommodate the volume expansion and contraction of tin during charge-discharge cycles, while maintaining electrical conductivity and preventing material degradation.
2Productivity
If tin particles are exposed to electrolyte, then lithium intercalation occurs, but unstable SEI film forms reducing cycle performance
Solution Approach 1:
The patent applies intermediary principle by introducing carbon and copper coating layers as intermediate barriers between the tin-based nanomaterial and the electrolyte. These coating layers mediate the interaction between tin and electrolyte, allowing lithium ion transport while preventing direct contact that would cause unstable SEI formation. The intermediary layers enable stable SEI formation on their surfaces instead, improving cycle performance.
3Reliability
If surface coating method is used to prevent pulverization, then cycle performance is improved, but conductivity may be reduced
Solution Approach 1:
The patent applies parameter changes principle by carefully controlling the thickness and composition parameters of the carbon and copper coating layers. The copper layer thickness is optimized to provide sufficient mechanical protection against pulverization while maintaining adequate electrical conductivity. The carbon layer parameters are adjusted to ensure structural stability without excessive resistance, achieving a balance between cycle performance improvement and conductivity preservation.
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 composite-coated nano-tin negative electrode material exhibits improved electrochemical cycling characteristics, including reduced volume expansion, stable SEI formation, and increased conductivity, leading to enhanced performance and potential applications in portable devices and electric vehicles.
Implementation Method 1
the nano-copper layer can relieve the volume expansion of the tin-based nanomaterial and has good plasticity
Implementation Method 2
coating a material with good conductivity on the surface of nano-tin increases its conductivity while avoiding direct contact between tin and the electrolyte, thus a stable SEI film forms
Data Source
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AI summary
The invention provides a composite-coated nano-tin negative electrode material, which comprises a tin-based nanomaterial, a nano-copper layer coated on the surface of the tin-based nanomaterial and a conductive protective layer coated on the surface of the nano-copper layer. The nano-copper layer can inhibit the volume expansion of nano-tin, keep the nano-tin material from cracking, avoid direct contact between nano-tin and electrolyte to form stable SEI and increase the conductivity of the electrode. Coating a conductive layer on the surface of the nano-copper layer can effectively inhibit the oxidation of nano-copper, thus improving its electrochemical performance. The composite-coated nano-tin negative electrode material according to the invention is used as a negative electrode material of a lithium-ion battery, has excellent electrochemical performance, and has potential application prospects in portable mobile devices and electric vehicles.