Boron-Coated Positive Electrode Material for Silicon-Anode Cycle Life
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Solution Overview
Problem
Secondary batteries face challenges in maintaining performance and sustainability due to high initial irreversibility and cycle performance deterioration, particularly when using silicon-based negative electrodes, which requires the development of effective positive electrode materials to enhance electrode density and reduce resistance differences.
Innovation Solution
A positive electrode material comprising first and second particles with cobalt and boron coating layers, differing in size, is used to improve electrode density and interfacial resistance, thereby reducing irreversible capacity and enhancing the service life of silicon-based negative electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a silicon-based active material is used in the negative electrode to develop high-capacity battery, then the battery capacity is improved, but the initial irreversibility becomes high
Solution Approach 1:
The patent changes the parameters of the positive electrode by using a bimodal particle size distribution with specific D10, D50, and D90 values, and by controlling the coating layer thickness to 1-10 nm, thereby optimizing the electrode density and resistance characteristics to compensate for the high initial irreversibility of silicon-based negative electrodes
Solution Approach 2:
The patent uses a composite positive electrode material consisting of a core active material (lithium nickel cobalt manganese oxide) with a surface coating layer containing cobalt and boron, creating a composite structure that optimizes both capacity and resistance characteristics
2Reliability
If the components of the positive or negative electrode are adjusted or additives are added to improve battery performance, then the battery performance is improved, but the sustainability may be adversely affected
Solution Approach 1:
The patent optimizes the particle size distribution parameters (D10, D50, D90) and coating layer composition to achieve high electrode density and stable resistance characteristics, thereby improving both performance and sustainability without requiring harmful additives
Solution Approach 2:
The patent applies a localized coating layer treatment on the surface of the positive electrode particles, creating different compositions at different locations (core vs. surface) to simultaneously improve performance and stability
3Ease of manufacture
If the positive electrode material uses single particle size, then the manufacturing process is simple, but the electrode density is low and resistance difference with negative electrode is high
Solution Approach 1:
The patent segments the positive electrode particles into different size ranges (D10, D50, D90) to create a bimodal distribution that improves electrode density by filling voids between larger particles with smaller particles, while still maintaining relatively simple manufacturing processes
Solution Approach 2:
The patent changes the particle size distribution parameters to optimize the electrode density and resistance characteristics, achieving high performance while maintaining manufacturing feasibility
Data Source
AI summary
Disclosed (or Provided) are a positive electrode material comprising: a first positive electrode active material which is in the form of single particles and has a coating layer including boron (B) and cobalt (Co) provided on at least a portion of the surface thereof; and a second positive electrode active material which has a lager particle diameter than that of the first positive electrode active material, is in the form of single particles and has a coating layer including boron (B) and cobalt (Co) provided on at least a portion of the surface thereof, and a positive electrode and a secondary battery including the same.