Positive Electrode Material Blending for Stable Battery Voltage Plateaus
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Solution Overview
Problem
Existing secondary batteries face challenges in improving capacity utilization and cycle performance due to significant differences in voltage plateaus between different types of positive electrode active materials, leading to accelerated capacity fade during charging and discharging.
Innovation Solution
A positive electrode active material comprising a polyanionic material and a ternary material with specific molecular formulas and modifications is used, ensuring close voltage plateaus and synergistic effects to enhance capacity utilization and cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If different types of positive electrode active materials are used to increase capacity, then the capacity utilization improves, but the voltage plateau difference increases leading to accelerated capacity fade
Solution Approach 1:
The patent modifies the molecular formulas of polyanionic and ternary materials by adjusting stoichiometric ratios (Li1+xFe1−yAyP1−zQzO4 where 0≤x≤0.3, 0≤y≤0.7, 0≤z≤0.5) to control voltage plateaus within 0.3V difference, enabling high capacity utilization while maintaining cycle performance
Solution Approach 2:
The patent creates a composite positive electrode active material combining polyanionic material (Li1+xFe1−yAyP1−zQzO4) and ternary material (LiNijCokM1dM2eOfRg) in specific ratios (60-95 wt% polyanionic, 5-40 wt% ternary) to achieve synergistic effects where both materials operate at similar voltage plateaus, preventing capacity fade while maximizing total capacity
2Quantity of substance
If polyanionic and ternary materials are combined to improve capacity, then the voltage plateau difference increases, but the cycle performance deteriorates due to accelerated capacity fade
Solution Approach 1:
The patent precisely controls the voltage plateau of ternary material to be within 0.3V of polyanionic material by adjusting molecular formula parameters (0.50≤j≤0.95, 0.05≤k≤0.50, 0.10≤l≤0.50, 0.05≤m≤0.50, 0.05≤n≤0.50), ensuring stable voltage composition during charging and discharging cycles
Solution Approach 2:
The patent applies different material compositions to different regions of the positive electrode, with polyanionic material forming the base (60-95 wt%) and ternary material (5-40 wt%) strategically combined to create local voltage stabilization zones where the two materials work synergistically at matching voltage plateaus
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 combination of polyanionic and ternary materials with optimized parameters improves the capacity utilization and cycle performance of secondary batteries by stabilizing redox potentials and reducing voltage disparities, thereby extending battery life and efficiency.
Implementation Method 1
The combination of polyanionic and ternary materials with optimized parameters improves the capacity utilization and cycle performance of secondary batteries by stabilizing redox potentials and reducing voltage disparities
Data Source
AI summary
Embodiments of this application relate to a positive electrode active material, a positive electrode plate, a secondary battery, and an electric device. The positive electrode active material includes a first active material and a second active material. The first active material includes a compound having a molecular formula of Li1+xFe1−yAyP1−zQzO4 and a modified compound thereof. The second active material includes a compound having a molecular formula of LihNijCokM1dM2eOfRg and a modified compound thereof. The embodiments of this application can improve capacity utilization and cycle performance of a secondary battery.