Lithium Battery Cathode Additive for Capacity and Efficiency
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Solution Overview
Problem
Lithium secondary batteries face limitations in achieving high capacity and efficient charge/discharge due to high irreversible capacity of silicon-based negative electrode active materials, requiring costly lithiation processes.
Innovation Solution
Incorporating a nickel-containing positive electrode active material with an additive comprising metal particles and lithium oxide, which react to form lithium ions and metal oxide within the battery's operating voltage range, reducing the need for separate lithiation and enhancing initial capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a high capacity silicon-based negative electrode active material is used, then the capacity of the lithium secondary battery is increased, but the charge and discharge efficiency becomes low due to high irreversible capacity
Solution Approach 1:
The patent applies preliminary action by incorporating a lithium source compound (such as Li2SiO3, Li3PO4, or Li2SiO2N) into the negative electrode active material before battery assembly. This pre-loaded lithium source compensates for the irreversible capacity loss that occurs during initial charging, eliminating the need for separate lithiation processes and improving charge-discharge efficiency while maintaining high capacity
2Loss of energy
If a separate lithiation process is performed to address the irreversible capacity limitation, then the charge and discharge efficiency is improved, but the manufacturing cost increases significantly
Solution Approach 1:
The patent merges the lithiation function into the negative electrode active material itself by incorporating lithium source compounds during electrode fabrication. This integration eliminates the need for separate lithiation processes, reducing manufacturing complexity and cost while maintaining improved charge-discharge efficiency
3Quantity of substance
If metal particles and lithium oxide are included in the positive electrode, then lithium ions are formed through reaction within the operating voltage range, but the device complexity increases
Solution Approach 1:
The patent applies self-service by designing the positive electrode to contain metal particles (such as Al, Si, or Ge) and lithium oxide that automatically react within the battery's normal operating voltage range (2.5-4.3V). This self-reacting system generates lithium ions in situ without requiring external intervention or complex control mechanisms, improving lithium ion availability while keeping the system simple
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 enables the production of lithium secondary batteries with improved capacity and charge/discharge efficiency at a lower cost, while reducing swelling and stability issues caused by CO or CO2 gases during charge/discharge cycles.
Implementation Method 1
the metal particles and the lithium oxide, which are included in the additive, are reacted at less than a driving voltage (2.5 V to 4.3 V) of a lithium secondary battery to form lithium ions and metal oxide
Implementation Method 2
the lithium ions move to a negative electrode to lithiate a negative electrode active material
Data Source
Figure 1
AI summary
Provided are a positive electrode and a lithium secondary battery which have high energy capacity and include a nickel-containing positive electrode active material, and an additive including metal particles and lithium oxide.