Nature Energy: Accurate monitoring of lithium battery status!

 

First author: Meng Li

Corresponding author: Boryann Liaw

Corresponding Unit: Idaho National Laboratory, USA

Achievements at a Glance

This study developed a novel non-destructive method to track the remaining amount of active lithium (Li) in lithium-ion batteries, similar to the fuel gauge in a car engine. By converting the theoretical capacity of transition metal oxides into lithium content analysis, the researchers were able to reliably track the lithium content in the electrode and reveal the impact of battery formulation and testing methods on performance. The study found that lithium content tracking was able to reveal stoichiometric changes near the electrode-electrolyte interface compared to capacity analysis.

By tracking four key variables from battery formation to end of life, the researchers used a thermodynamic framework to characterize electrode and battery performance. This precise lithium content utilization differential analysis is expected to enable more accurate battery engineering, evaluation, failure analysis and risk mitigation. This method may be applicable to all stages from battery cell design optimization, manufacturing to battery management, thereby improving battery performance and reliability.

Picture and text guide

Figure 1: Voltage vs. specific capacity curves for nine cells during formation cycles, and conversion of these results to equivalent voltage (Veq) vs. lithium content (x). The figure shows the cell performance for different cell formulations and test conditions.

Figure 2: Charge-discharge curve of a battery obtained through GITT experiment, and the relationship between Veq and specific capacity. The figure also shows the Veq and x curve after considering the theoretical capacity and utilization efficiency U, revealing the change of lithium content during charging and discharging.

Figure 3 shows the charge retention of three batteries during cycle aging at different Vmax charge cut-off voltages, and the corresponding progression of the Veq vs. x curves. These graphs reveal the changes in battery performance during cycle aging.

Figure 4: Tracking changes in key variables for the three batteries during cycle aging, including specific capacity retention, lithium content change, change in utilization factor U, and lithium content.

Figure 5: Tracking the reliance of different batteries on the anode to provide additional lithium content during cycling reveals the key factors in maintaining battery performance.

Highlights

1. An innovative non-destructive lithium content tracking method is proposed, which provides a new perspective for battery status assessment.

2. By tracking lithium content, we can more accurately analyze the factors affecting battery performance and life, which helps optimize battery design.

3. The research results show that the lithium content tracking method can improve the accuracy and reliability of battery engineering and help improve battery performance.

4. This method can be widely used in the design optimization, manufacturing and battery management of battery cells and has important practical application value.

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