Lithium-Ion Anode Prelithiation Using Temperature-Swing Formation
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Solution Overview
Problem
Lithium ion batteries face capacity fading due to lithium consumption during charging, leading to the formation of solid electrolyte interfaces (SEI) on the anode, which is exacerbated by the high activity of prelithiated anodes requiring controlled humidity conditions, increasing manufacturing costs and safety risks.
Innovation Solution
A method involving charging the battery to 4.2-4.5 V at a first temperature (45-65°C) and discharging to 2.5-3.2 V at 25°C, with alternating cycles to prelithiate the anode, allowing in-situ prelithiation without the need for external lithium and controlled assembly conditions, thereby stabilizing the SEI and improving battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external lithium metal is used for prelithiation, then capacity fading is compensated, but manufacturing cost increases and safety risks arise due to explosion hazards
Solution Approach 1:
The invention extracts the harmful element (external lithium metal) from the prelithiation process and replaces it with a safe alternative (lithium ions from cathode). The harmful external lithium metal is removed entirely, while the beneficial prelithiation effect is retained through in-situ lithium ion insertion during formation cycles
Solution Approach 2:
The invention introduces an intermediary mechanism (temperature-controlled formation cycles) to achieve prelithiation without direct lithium metal contact. The temperature differential during charging/discharging acts as an intermediary that drives lithium ion migration from cathode to anode, eliminating the need for hazardous external lithium metal
2Reliability
If external lithium metal is used for prelithiation, then capacity fading is compensated, but manufacturing cost increases due to controlled humidity requirements
Solution Approach 1:
The invention removes the requirement for controlled humidity environments by extracting the problematic external lithium metal application step. The prelithiation is achieved through normal formation cycles in standard atmospheric conditions, eliminating expensive humidity control infrastructure
Solution Approach 2:
The battery performs its own prelithiation during standard formation cycles without requiring external intervention or special environmental controls. The lithium ions are transferred from cathode to anode through the battery's own electrochemical processes during normal charging/discharging operations
3Reliability
If high temperature charging is used, then lithium insertion into anode is enhanced, but energy consumption increases
Solution Approach 1:
The invention uses periodic alternating temperature cycles during formation to achieve efficient prelithiation. High temperature is applied only during charging phases to enhance lithium insertion, then reduced during discharging phases, creating an energy-efficient periodic pattern rather than continuous high temperature operation
Solution Approach 2:
The invention dynamically changes the temperature parameter during formation cycles, applying high temperature (45-65°C) only when needed for lithium insertion during charging, then returning to normal operating temperature during discharging. This parameter modulation optimizes energy consumption while maintaining effective prelithiation
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 significantly enhances reversible capacity and cycling stability, reduces capacity fading, and eliminates the risk of explosion, while being cost and labor efficient, with the temperature difference controlling the degree of prelithiation and avoiding lithium dendrite formation.
Implementation Method 1
the amount of lithium that is extracted from the cathode and inserted into the anode is higher than that deserted from the anode
Implementation Method 2
by making the first temperature higher than the second temperature, the amount of lithium that is extracted from the cathode and inserted into the anode is higher than that deserted from the anode
Data Source
Figure 1~2
AI summary
Provided is a novel method for prelithiating an anode of lithium ion batteries, comprising the following steps: (a) charging the battery to a voltage from about 4.2 to about 4.5 V at a first temperature; and (b) discharging the battery to a voltage from about 2.5 to about 3.2 V at a second temperature which is about 20 to 40℃ lower than the first temperature. Also provided is a lithium ion battery comprising an anode thus prelithiated.