Core-Shell NMC Cathode Material for Low-Resistance Battery Stability
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Solution Overview
Problem
Lithium-ion batteries face issues with the NMC material's reactivity with electrolyte solutions, leading to a loss of energy storage capacity and potential thermal runaway due to cation mixing and oxygen release, which existing coatings like alumina oxide and titanium dioxide fail to adequately address due to low conductivity and complexity in industrial applications.
Innovation Solution
A cathode active material with a core-shell structure, where the core is lithium nickel manganese cobalt oxide and the shell comprises carbon material, reduced graphene oxide, metal oxide, or a lithium-containing composite, reducing charge transfer resistance and enhancing stability and capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alumina oxide or titanium dioxide coating is applied to NMC material, then stability and capacity retention are improved, but conductivity decreases and manufacturing complexity increases
Solution Approach 1:
The patent uses carbon material coating instead of complex atomic layer deposition techniques. Carbon material is inexpensive, easy to apply, and provides effective protection against electrolyte reaction while maintaining conductivity, resolving both the reliability improvement and manufacturing simplicity requirements
Solution Approach 2:
The patent employs composite shell structures containing carbon material combined with other materials (reduced graphene oxide, metal oxide, or lithium-containing composite) to achieve both high stability and high conductivity simultaneously, while the simple coating process maintains manufacturing ease
2Reliability
If alumina oxide coating is applied to NMC material, then capacity retention is improved, but battery resistance increases
Solution Approach 1:
Carbon material coating provides effective protection against electrolyte decomposition and capacity fade while maintaining excellent electrical conductivity, directly addressing the problem of increased resistance associated with alumina oxide coatings
Solution Approach 2:
The composite shell structure combines carbon material with conductive components (reduced graphene oxide, metal oxide, or lithium-containing composite) to ensure both high capacity retention and low resistance, overcoming the limitations of single-material coatings
3Quantity of substance
If NMC material is used for high capacity, then energy storage capacity is improved, but reactivity with electrolyte solution increases leading to thermal runaway
Solution Approach 1:
The shell coating is applied in advance to prevent harmful reactions between the NMC material and electrolyte solution before they occur. This preliminary protective layer blocks direct contact and prevents cation mixing and oxygen release that lead to thermal runaway
Solution Approach 2:
The composite shell structure provides both chemical inertness to prevent electrolyte reaction and electrical conductivity to maintain battery performance, allowing high-capacity NMC material to be used safely without thermal runaway risks
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 cathode active material with a core-shell structure significantly improves battery capacity and stability, extending cycle life by reducing charge transfer resistance and preventing reactions with electrolyte solutions, while maintaining high conductivity.
Implementation Method 1
alumina oxide and titanium dioxide have low conductivity... The cathode active material with a core-shell structure significantly improves battery capacity and stability, extending cycle life by reducing charge transfer resistance and preventing reactions with electrolyte solutions, while maintaining high conductivity
Implementation Method 2
the shell comprises any one of or a mixture of materials selected from a carbon material... a reduced graphene oxide... a metal oxide... and a lithium-containing composite... preventing reactions with electrolyte solutions
Implementation Method 3
a development of the cathode active material which is non-reactive to the electrolyte solution
Data Source
AI summary
The present invention relates to a cathode active material for a lithium-ion battery having a structure comprising a core and a shell, wherein the core comprises lithium nickel manganese cobalt oxide compound and the shell comprises any one of or a mixture of materials selected from a carbon material, a reduced graphene oxide, a metal oxide, and a lithium-containing composite in an appropriate specified amount. Further, the invention relates to a method for preparing said cathode active material, a battery cathode comprising the active material according to the invention and a method for preparing said cathode, and a battery comprising said cathode. The lithium-ion battery containing the cathode comprising the active material according to the present invention has improved stability, capacity, and cycle life, thus enabling more efficient industrial applications.