Transition Metal Metaphosphate Anode with Lithium Phosphate Coating
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Solution Overview
Problem
Lithium manganese phosphate (LiMnPO4) anode active materials have limitations in initial efficiency, reaction with lithium, and long-term battery life due to low activity, high reaction voltage, and volume changes during charge and discharge, which restrict their capacity and power output in lithium secondary batteries.
Innovation Solution
A transition metal-metaphosphate anode active material, such as M(PO3)2 where M is titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), ruthenium (Ru), palladium (Pd), or silver (Ag), with a carbon coating layer, is used, which improves stability, reactivity, and electrical conductivity, and is synthesized through a method involving a heat treatment of a precursor containing a transition metal oxide and phosphate.
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 reaction with lithium is slow
Solution Approach 1:
A lithium phosphate coating layer is applied to the surface of the transition metal metaphosphate particles. This coating layer acts as an intermediary that facilitates lithium ion transfer and reaction while maintaining the high energy density benefits of the metaphosphate structure. The coating improves initial efficiency by providing a controlled interface for lithium reaction without requiring bulk compositional changes.
Solution Approach 2:
The invention changes the surface chemical composition and structure parameters of the anode material by applying a lithium phosphate coating. This surface modification alters the reactivity parameters at the particle surface, enabling faster lithium reaction kinetics and improved initial efficiency while preserving the bulk material's high energy density characteristics.
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 lithium phosphate coating serves as a mediator that accelerates lithium reaction at the particle surface. It provides favorable reaction pathways and reduces activation energy barriers, enabling faster reaction speeds while maintaining the high energy density of the metaphosphate core structure.
Solution Approach 2:
The lithium phosphate coating is applied in advance to the metaphosphate particles before battery assembly. This preliminary surface treatment pre-establishes reactive sites and favorable surface chemistry that enable rapid lithium reaction from the first charge-discharge cycle, eliminating the need for slow initial reactions.
3Quantity of substance
If LiMnPO4 is used as an anode active material, then capacity is achieved, but voltage is low due to high reaction voltage with lithium
Solution Approach 1:
The invention applies local quality modification by coating only the surface of the particles with lithium phosphate, while maintaining the bulk metaphosphate composition that provides high capacity. The surface coating locally adjusts the reaction voltage characteristics without changing the overall stoichiometry and capacity-determining bulk structure.
4Quantity of substance
If LiMnPO4 is used as an anode active material, then capacity is achieved, but long-term life is limited due to volume changes
Solution Approach 1:
The lithium phosphate coating is applied beforehand to the metaphosphate particles to cushion against volume changes during charge-discharge cycling. This pre-applied protective layer accommodates expansion and contraction stresses, preventing particle cracking and structural degradation that would otherwise limit long-term battery life while maintaining capacity.
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-metaphosphate anode active material enhances capacity characteristics, reduces electrode resistance, and improves electrical conductivity, resulting in a higher battery voltage and better state of charge prediction, suitable for electric vehicle applications.
Implementation Method 1
a heat treatment of a precursor containing a transition metal oxide and phosphate
Implementation Method 2
with a carbon coating layer, which improves stability, reactivity, and electrical conductivity
Data Source
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AI summary
Provided is an anode active material including a transition metal-metaphosphate of Chemical Formula 1: <Chemical Formula 1> M(PO3)2 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.