LiF-embedded SiG Anode Coating for Battery Cycle Stability
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Solution Overview
Problem
Current lithium-ion batteries face challenges in achieving high energy storage capacities and cycle life due to the poor performance of silicon-based anodes, primarily due to volume changes during charging/discharging and high synthesis costs, which are not adequately addressed by existing materials and methods.
Innovation Solution
A nanographitic composite is developed for use as a lithium-ion battery anode, comprising electroactive material particles coated with graphene nanoplatelets and an SEI modifier additive, such as LiF, which forms a discontinuous or continuous thin solid electrolyte interface layer, enhancing cycle stability and reducing synthesis costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon particles are coated with carbon layers via chemical vapor deposition, then cycling stability is improved, but first cycle reversibility decreases due to retarded electrolyte penetration
Solution Approach 1:
The patent replaces thick carbon coating layers with thin graphene nanoplatelet coatings. Graphene's two-dimensional structure provides sufficient protection for cycling stability while its atomic-thin nature allows electrolyte penetration, resolving the contradiction between protection and accessibility.
Solution Approach 2:
The graphene nanoplatelet coating creates a porous, hierarchical structure that allows electrolyte penetration through interstitial spaces between platelets, maintaining first cycle reversibility while providing structural protection for cycling stability.
2Productivity
If graphene materials are used to coat silicon particles, then capacity and rate capability are improved, but the rigid framework cannot accommodate volume change during cycling
Solution Approach 1:
The patent uses individually coated silicon particles rather than aggregated structures, allowing each particle to expand and contract independently within its own graphene coating, accommodating volume changes while maintaining high capacity.
Solution Approach 2:
The graphene nanoplatelet coating provides a dynamic, flexible framework that can adapt to volume changes during lithiation-delithiation cycles, unlike rigid bulk graphene structures, thereby maintaining both capacity and structural stability.
3Quantity of substance
If traditional graphite anode materials are replaced with silicon, then energy storage capacity increases, but synthesis cost increases due to expensive precursors and complex processes
Solution Approach 1:
The patent changes the synthesis approach from complex chemical vapor deposition or hydrothermal methods to simple solution-based processing and drying, dramatically reducing synthesis cost while maintaining the high capacity benefits of silicon anodes.
Solution Approach 2:
The patent uses inexpensive graphene nanoplatelets as a coating material that can be applied through simple solution processing, replacing expensive and complex synthesis procedures with cost-effective materials and methods.
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 nanographitic composite improves the cycle life and energy storage capacity of silicon-based anodes, accommodating volume changes during cycling while maintaining electrical conductivity, and reduces production costs, making it suitable for commercial applications.
Implementation Method 1
a coating over the electroactive particles comprising a plurality of graphene nanoplatelets
Implementation Method 2
an SEI modifier additive wherein the SEI modifier additive is a dry powder that is disposed over at least part of the surface of the electroactive material particles
Data Source
AI summary
A nanographitic composite for use as an anode in a lithium ion battery is described, including: particles of an electroactive material; and a coating over the electroactive particles comprising a plurality of graphene nanoplatelets and an SEI modifier additive wherein the SEI modifier additive is a dry powder that is disposed over at least part of the surface of the electroactive material particles.