stabilizing lithium metal using ionic liquids for long-lived batteries - lithium ion battery cells

The suppression of the formation of shoot-Crystal of lithium metal anode during circulation is crucial for the implementation of lithium metal in the future
Based on battery technology.
Here, we report that before the battery is assembled, it can be achieved by simply dipping the electrode into the ionic liquid electrolyte for a period of time.
This creates a lasting lithium ion
Permeable solid electrolyte interface that allows Li | electrolyte | life4cells for commercial applications to perform a safe charge-discharge cycle of 1,000 cycles at Cullen efficiency> 99. 5%.
The customized solid electrolyte interface is based on N-propyl-N-
(II (fluorosulfonyl)
Malay room temperature ionic liquid containing lithium salt.
Formation is time-
And lithium salt.
The dynamic morphological changes are shown, and when optimized, the formation of shoot crystals and the consumption of electrolyte are prevented during circulation.
This work has shown that a simple, effective and commercially applicable lithium metal pretreatment process can bring commercially viable cycle life to lithium metal batteries.
Lithium foil metal (
China energy lithium battery, 0. 33u2009mm, 99%)
Immerse yourself in [CmPyr][FSI](Dai-
Qingxue, City Industrial Co. , Ltd. ,> 99%)
Electrolyte mixture containing 0.
5 mol kg lithium salt at different time periods (
4 u2009 h and 7, 12 and 18 days).
These lithium salts include the following: LiFSI (Dai-
Qingxue, City Industrial Co. , Ltd. ,> 95%), LiPF (Sigma, 98%)and LiAsF (Sigma-Aldrich, 98%).
Clean surface contaminants under lithium foil using nylon brushhexane (Merck).
Before storage and treatment in Ar atmosphere, dry ionic liquids at 100 °c using standard Schlenk line technology (less than 5u2009p. p. m. HO and 1u2009p. p. m. O).
Karl Fischer titration analysis of ionic liquids dried using this method shows that less than 10 p. p. m. HO content.
Lithium salt is dried, according to the literature.
After reaching the pre-treatment time required to drown the foil, remove them and rinse any residual electrolyte using the carbonate ester (DMC)(Fluka)
As mentioned earlier.
As mentioned earlier, the symmetrical Li | electrolyte | Li coin battery was made using a CR2032 metal jacket.
Using Maccor Series 4000 battery tester at ambient temperature, the symmetric battery has been tested for circulating charge and discharge electrostatic flow (22. 2±2u2009°C)
Low or high current density 0. 1 or 1.
0, mA, cm, respectively.
Copy coin cells cycle hundreds or thousands of cycles as specified in the text.
Charging and discharging time are 15 minutes respectively, and 30 minutes of rest between cycles (
Cycle is defined as charging step and discharge step).
The electrolyte used in symmetric batteries containing pre-treated electrodes is consistent with the electrolyte used for pre-treatment.
The lithium metal foil used throughout the experimental design has a diameter of 10mm and the measured electrolytic mass is 60 μ l.
After adding the cathode material, the All Li | electrolyte | LiFePO battery was prepared in the same way as the symmetric battery, and the electrolytic pretreatment and subsequent 1-C rate.
A composite lithium iron phosphate (
90 Weight %, Phostech)Carbon Black (2.
5 wt %, Timcal Super P)
And cmc cellulose adhesive (7. 5 wt%, Sigma-Aldrich)
Coating aluminum foil using an automatic pasting machine (
Massachusetts Institute of Technology, compact film coating machineAFA-III)
After drying, cut into a disc with a diameter of 10mm.
LiFePO and separator materials (Solupor)
Dry at 100 °c for 12 h in vacuum and then use in symmetric cells and whole cells. All cell-
Material Handling and battery manufacturing in Ar-
Glovebox working in less than 5 p with an inert atmosphere. p. m. HO and 1u2009p. p. m. O.
Repeat cells are recycled across all systems to ensure data reproduction.
Before the cycle, all cells experienced three formation cycles at the rate of C/10, and then experienced 1,000 cycles at the rate of 1 C (
The equivalent lithium current density is 1. 25u2009mAu2009cm)
The temperature is 30 °c.
Impedance measurements were performed using the Solartron 1255B frequency response analyzer, which has a signal amplitude of less than 10 mv and a frequency range of between 100 khz and 0. 1u2009Hz.
As mentioned earlier, after cleaning and drying the material with DMC, surface representation is performed after pretreatment or circulation.
The dry electrode is loaded and enclosed in the decay total reflection phase of the seal (
(Golden Gate)
Infrared analysis.
After the shell, the stage is removed from the glove box and the spectrum is obtained using the spectral 400 infrared spectrometer (Perkin-Elmer).
All spectra of 16 scans were recorded using 4-scancm resolution.
SEM using Philips XL-
A scanning electron microscope with 30 firing guns.
A specially designed brass substrate facilitates imaging of samples transferred to SEM through a sealed ambient chamber.
Under vacuum 1, the image is recorded with an accelerated voltage of 5 kv. 7 × 10mbar. A Link ISIS (
Oxford Instruments)energy-dispersive X-
Qualitative data on the surface of the sample are collected using a ray system.
VG310F spectrometer in micro laboratory (Thermo)
Used to collect XPS.
Introduce the sample into the instrument using a double-layer glove package (Sigma).
Transfer the sample from the glove box to the hand bag by storing the sample in the Schott bottle
Sealed aluminum laminated bag (3u2009M Film).
After 7 days of electrolyte pretreatment, all XPS measurements were recorded to ensure that sufficient time was detected to have expired.
Here's 7-
The day of the minimum electrolyte can be observed by SEM;
Therefore, the SEI information of the structure is best described by any spectral data, not the hole-
Residue.
According to the requirements, the corresponding authors provided data supporting the results of this study.