Gradient-Doped Positive Electrode Plate for Low-Resistance Li-Ion Diffusion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lithium ion batteries suffer from low discharge energy efficiency due to incomplete discharge and insufficient utilization of active substances, leading to reduced cycle performance and energy efficiency.
Innovation Solution
A positive electrode plate design with a positive active substance layer doped with a metal element M, where the doping amount of M gradually decreases in the thickness direction, enhancing the deintercalation ability of lithium ions and reducing diffusion resistance, thereby minimizing the difference in deintercalation ability between layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the positive active substance layer is made thicker to increase capacity, then the energy density is improved, but the diffusion resistance for lithium ions increases and discharge energy efficiency decreases
Solution Approach 1:
The patent applies local quality by creating a positive active substance layer with non-uniform doping distribution. The doping amount of metal element M varies through the thickness direction, with higher doping concentration near the current collector and lower concentration toward the outer surface. This gradient structure optimizes lithium ion deintercalation ability at different depths, reducing overall diffusion resistance while maintaining high capacity.
Solution Approach 2:
The patent changes the doping parameter of metal element M in the positive active substance layer. By controlling the doping amount to gradually decrease in the thickness direction and maintaining a specific ratio (≤8) between the doping amounts at different positions, the patent optimizes the balance between capacity and discharge energy efficiency, improving lithium ion diffusion without sacrificing storage capacity.
2Reliability
If the doping amount of metal element M is increased uniformly throughout the layer, then the deintercalation ability for lithium ions is enhanced, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent implements local quality by specifying that the doping amount of metal element M varies locally through the thickness direction of the positive active substance layer. This creates optimal deintercalation ability at each depth position without requiring complex manufacturing processes, as the gradient can be achieved through controlled doping during layer formation.
Solution Approach 2:
The patent optimizes the doping parameter by establishing a specific relationship: the doping amount gradually decreases in the thickness direction and the ratio between doping amounts at different positions is controlled to be ≤8. This parameter control achieves reliable deintercalation ability while maintaining manufacturability through standardized doping processes.
3Loss of energy
If the positive active substance layer is made thinner to reduce diffusion distance, then the discharge energy efficiency is improved, but the capacity and energy density decrease
Solution Approach 1:
The patent addresses the thickness dilemma by introducing a compositional dimension - varying the doping amount of metal element M through the thickness direction. This allows the layer to maintain sufficient thickness for high capacity while achieving enhanced deintercalation ability through optimized doping distribution, effectively resolving the contradiction by adding a compositional variable to the structural design.
Solution Approach 2:
The patent changes the doping parameter of metal element M to optimize the balance between layer thickness and performance. By controlling the doping amount to gradually decrease through the thickness with a ratio ≤8, the patent enables thicker layers to achieve high discharge energy efficiency without sacrificing capacity, as the gradient doping compensates for the increased diffusion distance.
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 design improves discharge energy by 5% to 20%, enhancing cycle performance and energy efficiency of the lithium ion battery.
Implementation Method 1
The positive active substance layer contains a positive active substance doped with a metal element M. The metal element M is configured to enhance deintercalation ability of the positive active substance for lithium ions.
Implementation Method 2
resistance of lithium ions to diffuse in the positive electrode plate is significantly reduced, while polarization of the lithium ions in a diffusion process of the positive electrode plate is inhibited
Data Source
Figure 1
AI summary
Provided are a positive electrode plate, a lithium ion battery, and an energy storage device. The positive electrode plate includes a positive current collector and a positive active substance layer. The positive active substance layer is disposed on at least part of a surface of the positive current collector. The positive active substance layer contains a positive active substance doped with a metal element M. A doping amount of the metal element M in the positive active substance of the positive active substance layer gradually decreases in a thickness direction away from the positive current collector. A ratio of a doping amount of the metal element M in the positive active substance of the positive active substance layer closest to the positive current collector to a doping amount of the metal element M in the positive active substance of the positive active substance layer farthest from the positive current collector is less than or equal to 8. According to the present disclosure, resistance of lithium ions to diffuse in the positive electrode plate is significantly reduced, while polarization of the lithium ions in a diffusion process of the positive electrode plate is inhibited, thereby improving cycle performance and energy efficiency of the lithium ion battery.