Transition Metal Pyrophosphate Anode Material for High Energy Density Batteries
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Solution Overview
Problem
Current anode active materials, such as lithium manganese phosphate, face limitations in initial efficiency, capacity manifestation, reaction speed, and long-term battery life due to low lithium reactivity and high reaction voltage, especially in plug-in hybrid electric vehicles and battery electric vehicles requiring high energy density and power characteristics.
Innovation Solution
A transition metal-pyrophosphate anode active material with a carbon coating layer, specifically M2P2O7 where M is chromium, nickel, ruthenium, or palladium, is developed, which enhances stability, reactivity, and electrical conductivity, reducing electrode resistance and solid electrolyte interface formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LiMnPO4 is used as an anode active material, then energy density is improved, but initial efficiency is low and capacity cannot be fully manifested
Solution Approach 1:
The patent changes the chemical composition parameters by replacing lithium with transition metals (Fe, Co, Ni, Cu, Mn) in the phosphate structure, creating Li1-xMxPO4 compounds. This parameter change allows tuning of both energy density and initial efficiency by adjusting the substitution ratio x, resolving the contradiction between high energy density and high initial efficiency
Solution Approach 2:
The patent creates composite materials by combining lithium phosphate with transition metal phosphates in a single crystal structure (Li1-xMxPO4). This composite approach integrates the high energy density of lithium phosphate with the improved reactivity of transition metal phosphates, simultaneously achieving both high initial efficiency and high energy density
2Use of energy by moving object
If LiMnPO4 is used as an anode active material, then energy density is improved, but reaction speed with lithium is slow
Solution Approach 1:
The patent changes the electronic structure parameters by introducing transition metals with different electron configurations into the phosphate lattice. These transition metals have varying d-electron counts that facilitate electron transfer and improve lithium ion diffusion kinetics, thereby increasing reaction speed while maintaining high energy density
Solution Approach 2:
The patent applies local quality changes by selectively substituting lithium atoms at specific lattice positions with transition metal atoms. This localized substitution creates regions with enhanced catalytic activity and improved lithium ion pathways, accelerating the overall reaction speed without compromising the bulk energy density
3Use of energy by moving object
If LiMnPO4 is used as an anode active material, then energy density is improved, but battery voltage is low
Solution Approach 1:
The patent changes the electrochemical potential parameters by selecting transition metals with different standard reduction potentials. By adjusting the type and ratio of transition metals (Fe, Co, Ni, Cu, Mn), the patent optimizes the open circuit voltage and operating voltage of the battery, achieving high energy density without sacrificing voltage
4Use of energy by moving object
If LiMnPO4 is used as an anode active material, then energy density is improved, but long-term life is limited due to volume changes
Solution Approach 1:
The patent creates composite materials with transition metal phosphates that have more stable crystal structures during lithium insertion/extraction. The transition metal components provide structural buffering that accommodates volume changes, reducing mechanical degradation and improving long-term cycling life while maintaining high energy density
5Reliability
If carbon-based material is used as anode active material, then initial efficiency is high, but energy density is low
Solution Approach 1:
The patent creates composite materials that combine the advantages of carbon-based materials (high initial efficiency, good conductivity) with transition metal phosphates (high energy density). The composite structure allows carbon to provide efficient electron transport and initial lithium insertion, while transition metal phosphates contribute high capacity and structural stability, achieving both high initial efficiency and high energy density
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 transition metal-pyrophosphate anode active material with a carbon coating layer improves capacity characteristics, increases battery voltage, and enables linear state of charge prediction, making it suitable for electric vehicles and power storage applications.
Implementation Method 1
a carbon coating layer on the transition metal-pyrophosphate, wherein a thickness of the carbon coating layer is in a range of 5 nm to 100 nm
Data Source
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AI summary
Provided is an anode active material including a transition metal-pyrophosphate of Chemical Formula 1 below: <Chemical Formula 1> M2P2O7 where M is any one selected from the group consisting of titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), ruthenium (Ru), palladium (Pd), and silver (Ag), or two or more elements thereof. Since the anode active material of the present invention is stable and has excellent conversion reactivity while including only transition metal and phosphate without using lithium in which the price thereof is continuously increased, the anode active material of the present invention may improve capacity characteristics.