MoP-MoP2 Coated Carbon Anode for Fast Lithium-Ion Charging
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Solution Overview
Problem
Current lithium secondary batteries with carbon-based anode active materials face high resistance and lithium metal precipitation during high-rate charging, leading to inefficient charging and discharging and reduced battery lifetime.
Innovation Solution
An amorphous carbon coating layer containing metal phosphides like MoP and MoP2 is formed on the surface of carbon-based materials to reduce resistance and prevent lithium metal precipitation, improving high-rate charging characteristics without compromising efficiency or lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a carbon-based material is applied as an anode active material, then high energy density is achieved, but high resistance is generated during lithium ion intercalation leading to low charging efficiency
Solution Approach 1:
The patent applies local quality by creating a coating layer with different properties than the bulk carbon material. The coating layer has specific compositional characteristics (carbon content 5-30 at%, metal phosphide content 70-95 at%) that differ from the underlying carbon-based anode material, providing localized functionality to reduce resistance while maintaining overall energy density
Solution Approach 2:
The patent uses composite materials by combining carbon-based material with metal phosphide compounds to form a coating layer. This composite structure integrates the high energy density advantage of carbon materials with the low resistance property of metal phosphides, achieving both high energy density and high charging efficiency
2Speed
If high-rate charging is performed, then charging speed is increased, but lithium metal precipitation occurs reducing battery lifetime
Solution Approach 1:
The patent applies preliminary anti-action by pre-forming a coating layer on the carbon-based anode material before lithium ion intercalation begins. This pre-formed coating layer with its specific compositional characteristics prevents lithium metal precipitation from occurring in the first place during high-rate charging, thereby protecting battery lifetime while enabling fast charging
3Reliability
If surface modification is performed to improve lithium ion mobility, then lifetime characteristics are improved, but lithium metal precipitation and capacity reduction problems persist
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional parameters of the coating layer (carbon content 5-30 at%, metal phosphide content 70-95 at%, thickness 1-100 nm). These specific parameter ranges optimize both lithium ion mobility and prevention of lithium metal precipitation, simultaneously improving lifetime characteristics and charging efficiency
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 amorphous carbon coating layer with metal phosphides enhances lithium ion mobility and stability, achieving improved high-rate charging and extended battery life by reducing surface resistance and suppressing lithium metal precipitation.
Implementation Method 1
reduces the resistance generated when intercalating lithium into the surface of a carbon-based material
Implementation Method 2
suppressing the precipitation of lithium metal
Data Source
AI summary
The present invention relates to an anode active material, a nonaqueous lithium secondary battery comprising the same, and a preparation method therefor, and the purpose of the present invention is to improve high-rate charging characteristics without deterioration of charging and discharging efficiency and lifetime characteristics when applying an amorphous carbon coating layer as the anode active material of the nonaqueous lithium secondary battery, wherein the amorphous carbon coating layer comprising MoPx particles composed of MoP and MoP2 is formed on the surface of a carbon-based material, thereby reducing resistance when intercalating lithium ions into the surface of the carbon-based material, and improving reactivity and structural stability of the surface. The anode active material according to the present invention comprises a carbon-based material, and an amorphous carbon coating layer comprising MoPx particles composed of MoP and MoP2 formed on the surface of the carbon-based material.