Composite Anode Material with Core-Shell Structure for Lithium Ion Batteries
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Solution Overview
Problem
The existing lithium ion batteries using graphite anodes face limitations in energy density due to the low capacity of carbon anode materials, while nickel oxide anodes suffer from volume change and poor conductivity, leading to poor cycling stability and high-rate charging/discharging performance.
Innovation Solution
A composite anode material with a core-shell structure is developed, where a non-active inert core, such as silicon carbide or silicon nitride, is coated with a thin layer of nickel oxide, which enhances the material's stability and conductivity without affecting lithium ion intercalation rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel oxide is used as anode material to increase capacity, then energy density is improved, but volume change during lithium ion intercalation/deintercalation causes material crush and poor cycling stability
Solution Approach 1:
The nickel oxide particles are divided into ultrafine particles with diameter of 1-10 μm, which segments the large volume change into smaller increments across multiple particles, reducing individual particle stress and preventing material crush
Solution Approach 2:
The nickel oxide ultrafine particles are embedded within a three-dimensional porous conductive skeleton structure, creating a nested configuration where the active material is protected and supported by the conductive framework, maintaining structural integrity during volume changes
2Ease of manufacture
If traditional manufacturing methods are used to produce nickel oxide, then production is simpler, but particle size is large causing poor conductivity and low lithium ion diffusion rate
Solution Approach 1:
The particle size parameter is changed from traditional large particles to ultrafine particles with diameter of 1-10 μm, which dramatically increases the lithium ion diffusion rate while the sol-gel method maintains manufacturing feasibility through chemical synthesis
3Reliability
If nickel oxide is coated with carbon material to improve conductivity, then conductivity performance is improved, but the coating layer blocks lithium ion access to nickel oxide reducing utilization rate
Solution Approach 1:
A three-dimensional porous conductive skeleton structure is created with high porosity, allowing lithium ions to access the nickel oxide ultrafine particles embedded within the pores while the conductive framework provides electron transport pathways, thus maintaining both conductivity and utilization rate
4Reliability
If carbon nanotube arrays are used to support nickel oxide nanoparticles, then utilization and conductivity are improved, but production cost increases significantly
Solution Approach 1:
The patent replaces expensive carbon nanotube arrays with a cost-effective porous conductive skeleton made from abundant materials, achieving the same functional support and conductivity enhancement at significantly lower production cost while maintaining high nickel oxide utilization
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
This configuration improves the cycling performance and energy density of lithium ion batteries by minimizing volume change and maintaining high-rate capability, while reducing production costs associated with carbon nanotube arrays.
Implementation Method 1
the porous conductive skeleton has a three-dimensional structure and high porosity, which not only provides a fast ion transfer channel but also effectively relieves the volume change of the active material
Implementation Method 2
The method comprises: preparing a sol by mixing a metal alkoxide and an alkaline solution, and performing a sol-gel process on the sol to obtain the porous conductive skeleton
Implementation Method 3
performing a sol-gel process on the sol to obtain the porous conductive skeleton
Implementation Method 4
The porous conductive skeleton has a three-dimensional structure and high porosity, which not only provides a fast ion transfer channel
Data Source
AI summary
The present invention provides a composite anode material including nickel oxide, a method for preparing the composite anode material, and a lithium ion battery using the composite anode material. The composite anode material has a core-shell structure, the inner core is an inert core comprising a non-active material, and the outer shell comprises an anode active material of nickel oxide. The composite anode material with core-shell structure in the present invention overcomes the problem of volume changing and chalking of nickel oxide during charging/discharging and obtains a better cycle performance and rate performance.