Alkaline Source Cathode Activation for Rechargeable Battery Capacity
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Solution Overview
Problem
Existing secondary batteries face challenges in achieving high specific capacity and good cyclability while maintaining safe operating conditions, particularly due to high initial irreversible capacity and limited energy density, especially when using silicon anodes and lithium or sodium ion systems.
Innovation Solution
The process involves combining a primary cathode active material with an alkaline source material like Li2O or Na2O and charging it at elevated temperatures and lower voltages to form a lithium- or sodium-activated cathode, which compensates for the initial irreversible capacity and enhances the battery's performance by supplying alkali ions within the electrolyte window stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-capacity anode materials like silicon are used to increase energy density, then the specific capacity is improved, but the initial irreversible capacity increases and cyclability deteriorates
Solution Approach 1:
The patent applies preliminary action by performing cathode activation before battery assembly. The cathode material is pre-activated at elevated temperatures (40-100°C) to form a stable surface layer and optimize ion transport pathways in advance, which compensates for the high initial irreversible capacity of silicon anodes and improves subsequent cyclability
2Reliability
If conventional cathode materials are used to maintain stability, then operating safety is improved, but energy density and specific capacity are limited
Solution Approach 1:
The patent applies parameter changes by modifying the cathode material properties through activation at elevated temperatures (40-100°C). This thermal treatment changes the surface chemistry and crystal structure parameters of the cathode material, enabling it to achieve higher energy density while maintaining operating safety through controlled activation conditions
3Reliability
If lithiated materials are used to ensure stable operation, then cyclability is improved, but lithium dendrite formation and safety issues occur
Solution Approach 1:
The patent applies the intermediary principle by introducing an alkaline earth metal compound (such as SrCO3, BaCO3, or SrSO4) as a mediator between the cathode material and lithium ions. This intermediary layer prevents direct contact and reactive interaction between lithium ions and the cathode material, eliminating lithium dendrite formation while maintaining stable cyclability
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
This approach results in secondary batteries with high specific capacity and improved cyclability, reducing the need for lithiated materials and preventing lithium dendrite formation, thus ensuring safe and efficient operation across multiple cycles.
Implementation Method 1
supplying alkali ions within the electrolyte window stability
Data Source
AI summary
A secondary battery including a cathode having a primary cathode active material and an alkaline source material selected from the group consisting of Na2O, Na2O2, Na2S, NaF, NaCl, NaBr, Li2O, Li2O2, Li2S, LiF, LiCl, LiBr, Na2O, Na2O2, Na2S, NaF, NaCl, and a mixture of any two or more thereof; an anode having an anode active material; an electrolyte; and a separator.