Supplemental Cathode Materials for Silicon-Anode Lithium-Ion Cells
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Solution Overview
Problem
Current lithium-ion batteries face challenges in achieving high energy density due to significant lithium loss during the first charge cycle, particularly with silicon-comprising anodes, leading to reduced performance and increased costs when using lithium supplements, and there is a need for improved methods to optimize lithium inventory in batteries.
Innovation Solution
Incorporating a supplemental cathode active material, such as lithium nickel oxide (Li2Ni1-xMxO2-yFy) with specific dopants like copper, iron, or manganese, into the cathode of lithium-ion batteries, which enhances the first-cycle coulombic efficiency and specific capacity, thereby improving energy density without the complexities of handling metallic lithium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If silicon-comprising anodes with high gravimetric capacity are used, then battery energy density is improved, but lithium loss during first charge cycle increases
Solution Approach 1:
The patent applies preliminary action by incorporating supplemental cathode active material before the first charge cycle to compensate for the lithium that will be lost during anode coating formation. This pre-positioning of lithium sources ensures that sufficient lithium is available throughout the battery's operational life, resolving the contradiction between using high-capacity silicon anodes and managing lithium loss.
Solution Approach 2:
The patent changes the parameter of cathode composition by adding supplemental active material with specific properties (different from the primary cathode material). This parameter change allows the system to maintain high energy density while compensating for lithium loss, as the supplemental material provides additional lithium inventory without compromising the primary cathode's performance.
2Reliability
If lithium supplements are added to compensate for lithium loss, then battery performance is maintained, but manufacturing complexity and cost increase
Solution Approach 1:
The patent merges the supplemental lithium source directly into the cathode structure by incorporating supplemental cathode active material during the same manufacturing process as the primary cathode. This integration eliminates the need for separate lithium supplementation steps, reducing manufacturing complexity while maintaining battery performance through adequate lithium inventory.
3Quantity of substance
If higher capacity cathode materials are used to compensate for lithium loss, then lithium inventory is improved, but first-cycle coulombic efficiency decreases
Solution Approach 1:
The patent applies local quality by using different cathode materials with different functions: the primary cathode material provides high voltage and main capacity, while the supplemental cathode material specifically provides additional lithium inventory. This functional differentiation allows the system to increase lithium inventory without significantly impacting first-cycle coulombic efficiency, as each material performs its specialized role.
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 use of supplemental cathode active materials increases the first-charge specific capacity and overall energy density of lithium-ion batteries, reducing lithium loss and improving cycle life, while maintaining low internal resistance and cost-effectiveness.
Implementation Method 1
Incorporating a supplemental cathode active material, such as lithium nickel oxide (Li2Ni1-xMxO2-yFy) with specific dopants like copper, iron, or manganese, into the cathode of lithium-ion batteries, which enhances the first-cycle coulombic efficiency and specific capacity
Implementation Method 2
an electrolyte ionically coupling the anode and the cathode
Data Source
AI summary
A lithium-ion battery includes an anode current collector, a cathode current collector, an anode disposed on and/or in the anode current collector, and a cathode disposed on and/or in the cathode current collector, and an electrolyte ionically coupling the anode and the cathode. In some embodiments, the anode includes silicon and carbon, and the cathode includes (1) a primary cathode active material and (2) a supplemental cathode active material. In some embodiments, a mass fraction of the silicon in the anode is in a range of about 10 wt. % to about 60 wt. %.