Manganese Cathode Precursors With Organic-Acid Morphology Control
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Solution Overview
Problem
Existing cathode active materials for lithium-ion batteries, particularly those with high manganese content, suffer from limited cycle life, voltage fade, and reduced energy density retention.
Innovation Solution
A process for producing manganese composite (oxy)hydroxides with a specific particle diameter and morphology, involving co-precipitation of manganese, nickel, and optional metals with alkali metal hydroxide and an organic acid, followed by calcination with lithium salts to form cathode active materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high manganese content is used in cathode active materials to increase energy density, then volumetric energy density is improved, but cycle life and energy density retention deteriorate
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the inner core contains high manganese content (0.6-0.8 mol fraction) for high energy density, while the outer shell contains protective elements (aluminum, magnesium, or lithium) that prevent degradation. This spatial differentiation allows the material to simultaneously achieve high energy density from the manganese-rich core and improved cycle life from the protective shell.
Solution Approach 2:
The invention uses composite materials by combining manganese with aluminum, magnesium, or lithium to form a composite cathode active material with formula Li1-yM1-xMxO2 where M1 includes Mn, Ni, Co, Al, Mg, and/or Li. This composite approach allows the material to benefit from the high capacity of manganese while the other elements provide structural stability and protection against degradation, thereby improving cycle life and voltage fade resistance.
2Quantity of substance
If high manganese content is used to increase energy density, then volumetric energy density is improved, but voltage fade increases
Solution Approach 1:
The patent creates a core-shell structure where the manganese-rich core (0.6-0.8 mol fraction Mn) provides high energy density while the outer shell containing aluminum, magnesium, or lithium maintains voltage stability. The shell acts as a protective layer that prevents Jahn-Teller distortion and structural degradation during lithium insertion/extraction cycles, thereby reducing voltage fade while preserving the high capacity benefits of high manganese content.
Solution Approach 2:
The invention employs composite materials with formula Li1-yM1-xMxO2 where the composite structure combines manganese (for high capacity) with aluminum, magnesium, or lithium (for voltage stability). The synergistic interaction between these elements in the composite material suppresses voltage fade by maintaining structural integrity during electrochemical cycling, allowing the material to retain both high energy density and voltage stability.
3Ease of manufacture
If conventional co-precipitation methods are used to form precursors, then manufacturing simplicity is maintained, but precursor morphology and particle size control are insufficient
Solution Approach 1:
The patent introduces an organic acid (such as citric acid, oxalic acid, or tartaric acid) as an intermediary agent during the co-precipitation process. This organic acid acts as a complexing agent that controls the precipitation kinetics and serves as a structure-directing template, enabling precise control over precursor particle size (5-20 μm) and morphology while maintaining a relatively simple one-pot synthesis procedure. The organic acid mediates between the metal salts and hydroxide to achieve uniform particle formation.
Solution Approach 2:
The invention applies parameter changes by systematically optimizing several process parameters: pH range (9-11), temperature (20-80°C), metal salt ratios (Ni:Mn:Co in 1:2:0.5 to 1:3:0.25), and organic acid concentration (0.1-1 M). These parameter adjustments transform the conventional co-precipitation process into a controlled synthesis method that produces precursors with specific particle sizes (5-20 μm) and desirable morphologies, thereby achieving manufacturing precision without significantly complicating the process.
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 resulting cathode active materials exhibit improved volumetric energy density, energy density retention, and excellent morphology, leading to enhanced electrochemical performance and extended battery lifespan.
Implementation Method 1
combining (a) an aqueous solution containing salts of nickel and of manganese, and, optionally, at least one of Al and Mg, or transition metals other than nickel and manganese wherein at least 50 mole-% of the metal is manganese, (b) with an aqueous solution of an alkali metal hydroxide and (c) an organic acid or its alkali or ammonium salt
Implementation Method 2
an organic acid or its alkali or ammonium salt wherein said organic acid bears at least two functional groups per molecule and at least one of the functional groups is a carboxylate group
Implementation Method 3
The calcination—or firing—generally also referred to as thermal treatment or heat treatment of the precursor—is usually carried out at temperatures in the range of from 600 to 1,000° C. During the thermal treatment a solid state reaction takes place
Implementation Method 4
During the thermal treatment a solid state reaction takes place, and the electrode active material is formed
Data Source
AI summary
Process for making a manganese composite (oxy)hydroxide with a mean particle diameter D50 in the range from 2 to 16 μm comprising the step(s) of combining (a) an aqueous solution containing salts of nickel and of manganese, and, optionally, at least one of Al, Mg, or transition metals other than nickel and manganese wherein at least 50 mole-% of the metal is manganese, (b) with an aqueous solution of an alkali metal hydroxide and (c) an organic acid or its alkali or ammonium salt wherein said organic acid bears at least two functional groups per molecule and at least one of the functional groups is a carboxylate group.