Lithium Secondary Battery Prelithiation Method for Capacity and Cycle Life
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Solution Overview
Problem
Lithium secondary batteries using metal-based anode active materials face issues with capacity drop and short cycle life due to volume changes during charging/discharging, and cathode active materials with Mn3+ ions cause degradation of the solid electrolyte interphase (SEI) layer, leading to reduced battery performance.
Innovation Solution
A method for prelithiation that uniformly predopes lithium into the anode of lithium secondary batteries, preventing metal ion penetration from the cathode and improving capacity and cycle life by connecting electrodes of the same polarity, adding an electrolyte solution, and doping the anode with a lithium metal plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a metal-based anode active material (silicon or tin) is used to achieve higher charge/discharge capacity, then the capacity is improved, but the anode experiences cracking and pulverization due to large volume change during lithium charging/discharging, resulting in drastic capacity drop and short cycle life
Solution Approach 1:
The patent applies preliminary action by introducing lithium metal particles into the anode active material before the battery is assembled and before any charging/discharging cycles occur. This pre-doping of lithium compensates for the initial capacity loss and stabilizes the anode structure, preventing the cracking and pulverization that would otherwise occur during subsequent volume changes, thereby extending cycle life while maintaining high capacity
2Quantity of substance
If a cathode active material with Mn3+ ions (such as nickel, manganese, or cobalt-based material) is used to achieve high capacity, then the capacity is improved, but Mn3+ ions undergo disproportionation reaction and release into the electrolyte solution, causing significant degradation in cycle and storage characteristics
Solution Approach 1:
The patent applies preliminary anti-action by introducing lithium metal particles that react with and neutralize the Mn3+ ions before they can undergo disproportionation and degrade the battery performance. This preemptive chemical counteraction prevents the harmful reaction sequence, maintaining both the high capacity benefits of Mn3+ cathode materials and the cycle life stability
3Ease of manufacture
If conventional lithiation methods are used, then the battery can be assembled, but the anode does not receive sufficient uniform lithium doping, resulting in high initial irreversible capacity and poor battery performance
Solution Approach 1:
The patent introduces lithium metal particles as an intermediary substance that facilitates uniform lithium distribution throughout the anode active material. These particles act as lithium reservoirs that gradually release lithium ions during charging, ensuring uniform doping concentration and improving manufacturing precision without complicating the assembly process
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 method ensures a low initial irreversible capacity and prevents cathode metal ion penetration onto the anode surface, significantly enhancing battery capacity and cycle life.
Implementation Method 1
produces electrical energy by an oxidation/reduction reaction when the lithium ions intercalate and deintercalate on the cathode and the anode
Implementation Method 2
doping the anode
Data Source
AI summary
The present disclosure relates to a method for prelithiation, and in particular, to a method for prelithiation that predopes lithium into at least one unit cell uniformly in large amounts. According to an aspect of the present disclosure, there is provided a method for prelithiation including an preparing at least one unit cell, the unit cell comprising a cathode, an anode, and a separator interposed between the cathode and the anode, disposing the prepared at least one unit cell in a reaction tank, and connecting electrodes having the same polarity, adding an electrolyte solution into the reaction tank, disposing a lithium metal plate in the electrolyte solution, and connecting the lithium metal plate to the anode, and doping the anode.