Coated Electrode Active Material for Stable Li-Ion Batteries
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Solution Overview
Problem
Lithium ion batteries face issues with undesired reactions on the surface of cathode active materials, leading to instability and inefficiency, despite existing coating methods like aluminum oxide or calcium oxide, which still require process improvements for uniformity and effectiveness.
Innovation Solution
A process involving particulate electrode active materials treated with compounds like Al, B, or Mg, followed by a heating post-treatment in a rotary or pendulum kiln, to achieve a coated material with high surface coverage and stability, ensuring minimal interference with lithium exchange during charging and discharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cathode active material surface is left untreated, then the manufacturing process is simple, but undesired reactions occur on the surface leading to instability
Solution Approach 1:
The patent applies preliminary action by coating the cathode active material surface with aluminum oxide or calcium oxide before battery assembly. This pre-coating prevents undesired reactions between the electrolyte/solvent and the cathode material surface, thereby improving reliability without adding complex operational steps during battery use.
Solution Approach 2:
The patent uses aluminum oxide or calcium oxide as intermediary coating materials that act as a barrier between the electrolyte/solvent and the cathode active material surface. These intermediary layers prevent direct contact and undesired reactions, improving stability while maintaining a relatively simple manufacturing process.
2Reliability
If a coating is applied to protect the cathode surface, then stability against undesired reactions is improved, but the manufacturing efficiency decreases
Solution Approach 1:
The patent employs a simple coating approach using readily available materials like aluminum oxide or calcium oxide that can be applied through straightforward processes. The coating is designed to be thin and sufficient for protection, avoiding complex multi-layer structures or expensive materials, thereby maintaining manufacturing efficiency while improving surface stability.
3Reliability
If a coating is applied to protect the cathode surface, then stability is improved, but uniformity of coating coverage is insufficient
Solution Approach 1:
The patent optimizes coating parameters including the choice of coating materials (aluminum oxide or calcium oxide), coating thickness, and heating temperature (300-800°C) to achieve uniform coverage. By carefully controlling these parameters, the patent ensures consistent and uniform coating application across the cathode active material surface, improving both stability and manufacturing precision.
4Reliability
If the coating thickness is increased to improve protection, then stability is improved, but lithium exchange during charging and discharging is hindered
Solution Approach 1:
The patent applies a thin coating layer that provides sufficient surface protection while maintaining lithium ion conductivity. The coating is designed with local quality - thin enough to allow lithium exchange but sufficient to prevent undesired reactions. This optimized thickness ensures both surface stability and efficient lithium transport during charging and discharging cycles.
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 process results in coated electrode active materials with enhanced stability, reduced impedance growth, improved cycle life, and low agglomeration tendencies, demonstrating superior electrochemical behavior.
Implementation Method 1
treating said electrode active material with a compound of M1... wherein said compound of M1 does not act as a cathode active material on its own
Implementation Method 2
performing a post-treatment by heating the material obtained after the step (b) or (c), if applicable, at a temperature from 300 to 800° C. in a rotary kiln or pendulum kiln
Data Source
AI summary
Process for making a coated electrode active material wherein said process comprises the following steps: (a) providing a particulate electrode active material according to general formula Li1+xTM1−xO2, wherein TM is a combination of Ni, Co and, optionally, Mn, and, optionally, at least one metal selected from Mg, Al, Ba, Ti and Zr, and x is in the range of from zero to 0.2, wherein at least 15 mole-% of the transition metal of TM is Ni, (b) treating said electrode active material with a compound of M1, wherein M1 is selected from Li, Al, B, Mg, Si, Sn, and from transition metals, or a combination of at least two of the foregoing, with or without a solvent, wherein said compound of M1 does not act as a cathode active material on its own, (c) optionally, removing compound of M1 which is not deposited on said particulate electrode active material, (d) performing a post-treatment by heating the material obtained after the step (b) or (c), if applicable, at a temperature from 300 to 800° C. in a rotary kiln or pendulum kiln.