Mn-Enriched Precursor Synthesis via Reducing Agent
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Solution Overview
Problem
Current lithium composite transition metal oxides face challenges in synthesis due to Mn oxidation during precursor preparation, leading to difficulties in achieving high energy density and stability, especially for medium and large batteries used in electric vehicles and power storage systems.
Innovation Solution
A transition metal precursor with a specific composition, including a reducing agent like sugar-based materials and anion substitution, is prepared using a co-precipitation method to prevent Mn oxidation, enhancing crystallizability, spheroidization, and tap density, resulting in improved electrochemical characteristics when used as a cathode active material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If Mn-enriched (1-x)LiMO2-xLi2MO3 based materials are synthesized using co-precipitation method, then high energy density can be achieved, but Mn is easily oxidized by dissolved oxygen during synthesis making synthesis difficult
Solution Approach 1:
The patent applies preliminary anti-action by adding a reducing agent before oxidation can occur. The reducing agent is introduced into the aqueous transition metal solution prior to co-precipitation, creating a reducing environment that prevents Mn oxidation by dissolved oxygen during the synthesis process, thereby enabling successful synthesis of Mn-enriched materials with high energy density
Solution Approach 2:
The patent converts the harmful effect of dissolved oxygen (which oxidizes Mn) into a beneficial process by introducing a reducing agent. The reducing agent reacts with dissolved oxygen to eliminate it, transforming the oxidation risk into a controlled reduction process that protects Mn from oxidation while enabling the synthesis of high-energy-density Mn-enriched materials
2Reliability
If surface treatment, core-shell structure formation, or hetero element substitution is used to prevent Mn oxidation, then oxidation resistance improves, but additional costs and process complexity increase
Solution Approach 1:
The patent applies preliminary action by adding the reducing agent at the beginning of the synthesis process, before co-precipitation occurs. This preliminary addition ensures Mn protection from oxidation throughout the entire synthesis process without requiring subsequent surface treatment or core-shell structure formation steps, thereby maintaining reliability while avoiding additional process complexity
Solution Approach 2:
The patent extracts the harmful dissolved oxygen from the system by introducing a reducing agent that reacts with and removes oxygen before it can oxidize Mn. This extraction approach prevents oxidation without requiring complex surface treatments or hetero element substitutions, achieving oxidation resistance through a simplified process
3Ease of manufacture
If reducing agent is added to prevent Mn oxidation, then synthesis feasibility improves, but precursor tap density deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the type and amount of reducing agent used. By selecting appropriate reducing agents and controlling their concentration, the patent maintains synthesis feasibility while minimizing negative effects on precursor tap density, achieving a balance between synthesis ease and product quality
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 approach facilitates easy electrode preparation and enhances the initial discharge capacity, efficiency, and lifespan of lithium secondary batteries, addressing the limitations of existing materials by improving the synthesis process and electrochemical performance.
Implementation Method 1
Mn is easily oxidized by dissolved oxygen inside an aqueous transition metal solution during synthesis of a transition metal precursor through a co-precipitation method
Implementation Method 2
A transition metal precursor with a specific composition, including a reducing agent like sugar-based materials
Implementation Method 3
synthesis of a transition metal precursor through a co-precipitation method
Data Source
AI summary
Disclosed are a precursor for preparation of a lithium composite transition metal oxide, a method for preparing the same and a lithium composite transition metal oxide obtained from the same. More particularly, the transition metal precursor which has a composition represented by Formula 1 below and is prepared in an aqueous transition metal solution, mixed with a transition metal-containing salt, including an alkaline material, the method for preparing the same and the lithium composite transition metal oxide obtained from the same are disclosed.MnaMb(OH1-x)2-yAy (1)wherein M is at least one selected form the group consisting of Ni, Ti, Co, Al, Cu, Fe, Mg, B, Cr, Zr, Zn and Period II transition metals; A is at least one selected form the group consisting of anions of PO4, BO3, CO3, F and NO3, and 0.5≤a≤1.0; 0≤b≤0.5; a+b=1; 0<x<1.0; and 0≤y≤0.02.