Boron-Coated Cathode Material for Capacity and Energy Retention
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Solution Overview
Problem
Existing lithium batteries face challenges in achieving high energy retention rates and initial gram capacity, particularly with lithium-rich manganese-based materials that suffer from fast energy attenuation and low initial capacity due to structural instability and lithium leaching.
Innovation Solution
A positive electrode active material is developed with a matrix of Li[LixNiaCobMncMd]O2 coated with a boron-containing alloy, which enhances lithium ion migration and structural stability, reducing energy loss and improving capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium-rich manganese-based materials are used to increase initial gram capacity, then the battery can store more energy, but the material suffers from structural instability and fast energy attenuation during long cycles
Solution Approach 1:
The patent applies composite materials by combining lithium-rich manganese-based matrix material with a boron-containing alloy coating layer. The matrix provides high initial gram capacity while the coating layer stabilizes the structure during cycling, preventing energy attenuation. This composite structure resolves the contradiction between achieving high capacity and maintaining long-term reliability.
Solution Approach 2:
The boron-containing alloy coating is applied locally on the surface of the lithium-rich manganese-based matrix particles. This local modification provides structural stability and protects against lithium leaching at the critical grain boundaries and surfaces, while the bulk matrix retains its high capacity characteristics. The local quality enhancement resolves the contradiction between high initial capacity and long-term energy retention.
2Speed
If the battery operates at high temperature to improve reaction kinetics, then lithium ion migration speed increases, but the structural instability of lithium-rich manganese-based materials is exacerbated
Solution Approach 1:
The boron-containing alloy coating is applied locally on the surface of the lithium-rich manganese-based matrix particles. This local modification provides structural stability and protects against lithium leaching at the critical grain boundaries and surfaces, while the bulk matrix retains its high capacity characteristics. The local quality enhancement resolves the contradiction between high initial capacity and long-term energy retention.
Solution Approach 2:
The boron-containing alloy coating changes the physical and chemical parameters of the material surface, including enhanced electronic conductivity and improved structural stability at elevated temperatures. This parameter modification allows the battery to operate at higher temperatures with improved lithium ion kinetics without suffering from the structural instability that would otherwise occur in the uncoated lithium-rich manganese-based material.
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 boron-containing alloy coating improves energy retention rate and initial gram capacity by stabilizing the matrix and facilitating lithium ion migration, thereby enhancing the battery's performance in long cycles.
Implementation Method 1
a coating layer, where the coating layer is disposed on a surface of the matrix, and the coating layer includes boron-containing alloy
Implementation Method 2
migration dynamics of lithium ions on a surface of the positive electrode active material can be improved
Implementation Method 3
the coating layer is in a molten fluid state at a high temperature, has good wettability on a grain boundary with high surface energy, and can be uniformly distributed on the matrix
Implementation Method 4
a compound including the transition metal and the boron has good structural stability and high-temperature resistance performance
Data Source
AI summary
Embodiments of this application provide a positive electrode active material, a battery cell, a battery, and a power consuming apparatus. The positive electrode active material includes: a matrix, where a chemical formula of the matrix is Li[LixNiaCobMncMd]O2, M includes at least one of Mg, Nb, Cr, Ce, Fe, Ta, B, Al, V, Ti, Zr, Sn, P, and Mo, x+a+b+c+d=1, x>0, a>0, 0<b<0.1, c>0, and d≥0; and a coating layer, where the coating layer is disposed on a surface of the matrix, and the coating layer includes boron-containing alloy. The technical solutions of this application can improve an energy retention rate and an initial gram capacity of a battery.