Nickel-Rich Cathode Cerium Doping for Higher Oxygen-Release Energy
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Solution Overview
Problem
Lithium-ion batteries, particularly nickel-rich cathodes, face challenges with low oxygen-release energy, leading to undesirable self-heating events due to lower thermal stability.
Innovation Solution
Incorporating cerium as a rare-earth element into the cathode, either as a dopant or coating, to increase the oxygen-release energy threshold, with compositions ranging from 7.5% to 10% cerium by weight, enhancing the thermal stability and reducing oxygen release acuteness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If nickel-rich cathode materials are used to increase energy density, then energy density is improved, but thermal stability deteriorates due to lower oxygen-release energy
Solution Approach 1:
The patent applies local quality by introducing rare-earth elements (specifically cerium, neodymium, or praseodymium) at specific locations within the cathode structure - either as dopants substituting for nickel atoms in the lattice or as surface coatings. This localized modification of specific regions of the cathode material improves thermal stability by raising the oxygen-release energy threshold while preserving the bulk nickel-rich composition that provides high energy density.
Solution Approach 2:
The patent employs composite materials by combining nickel-rich cathode materials with rare-earth elements to create a hybrid structure. The composite consists of the base nickel-containing oxide (providing high capacity) combined with rare-earth oxides or doped rare-earth atoms (providing thermal stability). This composite approach allows simultaneous achievement of high energy density and improved thermal safety.
2Reliability
If rare-earth elements are added to increase oxygen-release energy threshold, then thermal stability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentration of rare-earth elements within specific ranges (2-10 atomic percent as dopant, or 5-50 nm as coating thickness). By optimizing these parameters, the patent achieves sufficient thermal stability improvement without excessive rare-earth content that would complicate manufacturing. The defined parameter ranges provide clear manufacturing targets that balance performance improvement with process feasibility.
3Object-affected harmful factors
If cerium is used as rare-earth element to enhance thermal stability, then oxygen release acuteness is reduced, but energy density may be affected
Solution Approach 1:
The patent applies partial action by using moderate concentrations of cerium (2-10 atomic percent as dopant or 5-50 nm as coating) rather than excessive amounts. This partial incorporation of cerium is sufficient to raise the oxygen-release energy threshold and reduce oxygen release acuteness, while minimizing the displacement of high-capacity nickel atoms, thereby preserving most of the energy density.
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 increased oxygen-release energy threshold reduces the occurrence and severity of self-heating events, improving thermal stability and safety of lithium-ion batteries, while maintaining energy density within optimal ranges.
Implementation Method 1
The rare-earth element may be cerium... such that the second electrode has a higher oxygen-release energy than the same electrode free of the rare-earth element... increase the threshold release energy for oxygen to at least 90 kJ/mol
Data Source
AI summary
Electrodes, electrochemical cells having higher threshold oxygen-release energies, and methods of making the same are disclosed. The electrodes may be a nickel-rich cathode with up to 10% of a rare-earth element such as cerium. The rare-earth element may be added by doping during the manufacture of the cathode or by applying a coating on a surface of the cathode.