Cathode Active Material Composition for High-Temperature Capacity Retention
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Solution Overview
Problem
Existing positive electrode active materials for solid-state rechargeable batteries, such as nickel-manganese-cobalt (NMC) and nickel-cobalt-aluminium (NCA) oxides, exhibit limited capacity retention at higher temperatures and voltages, leading to increased capacity leakage (Qtotal) during charge-discharge cycles.
Innovation Solution
A method for manufacturing a positive electrode active material comprising lithium (Li), oxygen (O), and a mixture of cobalt (Co), manganese (Mn), and additional elements like B, Mg, Al, Nb, Ti, W, Y, Ca, S, P, Sn, Si, and Zr, with specific mol % ranges, involving a slurry preparation, mixing with cation and anion precursors, filtering, and heating between 300°C to 1000°C to form a lithium mixed metal oxide powder with improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional positive electrode active materials (NMC, NCA) are used, then high capacity is achieved, but capacity retention deteriorates at high temperature and voltage
Solution Approach 1:
The patent modifies the chemical composition parameters of the positive electrode active material by incorporating specific elements (W, Mo, Re) in controlled amounts (0.1-5.0 wt%) into the NMC or NCA structure. This compositional parameter change enhances capacity retention at high temperature and voltage while maintaining high capacity, directly resolving the technical contradiction between quantity of substance and reliability.
Solution Approach 2:
The patent creates a composite material system by combining conventional NMC or NCA base materials with additional metal elements (W, Mo, Re). This composite approach integrates the high capacity characteristics of NMC/NCA with the stability benefits of the added elements, achieving both high capacity and improved capacity retention under harsh conditions.
2Power
If higher voltage and temperature operation is implemented, then energy density is improved, but capacity leakage increases
Solution Approach 1:
The patent changes the material composition parameters by adding W, Mo, or Re elements to the positive electrode active material. This modification enables the material to operate at higher voltages and temperatures with reduced capacity leakage, allowing improved energy density without the harmful side effect of excessive capacity leakage.
Solution Approach 2:
The patent converts the potential harm of high voltage and temperature operation (which causes capacity leakage) into a benefit by using W, Mo, or Re additives. These elements stabilize the material structure under harsh conditions, transforming the operating conditions that would normally cause harm into conditions that can be exploited for higher energy density with controlled leakage.
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 method results in a positive electrode active material with reduced capacity leakage (Qtotal) at high temperatures, specifically below 55 mAh/g at 80°C, enhancing the stability and electrochemical properties of solid-state rechargeable batteries.
Implementation Method 1
heating between 300°C to 1000°C to form a lithium mixed metal oxide powder
Data Source
AI summary
Method for manufacturing positive electrode active material for batteries comprising Li, O and M, wherein M consists of: —Co between 5 and 35 mol %; —Mn less than 35 mol %; —A less than 10 mol %, A being an element from: B, Mg, Al, Nb, Ti, W, Y, Ca, S, P, Zr, Sn, Si and W, and—The balance Ni, Which comprises: Step 1: preparing a liquid slurry of a lithium mixed metal oxide powder, Step 2: mixing the powder before or after or during step 1 with a cation selected from: Ala3+, La3+, Co2+, Co3+, Mn2+, Mn3+, Mn4+, Mn6+, Zn2+, Cu+, Cu2+, B3+, Mg2+, and with an anion having a general formula A′yOz′−x′, wherein A′ is: B, Al, Sn, Si, P, W, wherein 0.5≤x≤4, 0.5≤y′≤2 and 1≤z′≤≤12; Step 3: drying said slurry; Step 4: heating the slurry resulting from steps 1 and 2 or the dried slurry from step 3.