Methodologies for Design, Characterization and Testing of Electrolytes that Enable Extreme Fast Charging of Lithium-ion Cells

Gao, Nan; Kim, Sangwook; Chinnam, Parameswara Rao; Dufek, Eric J.; Colclasure, Andrew M.; Jansen, Andrew N.; Son, Seoung‐Bum; Bloom, Ira; Dunlop, Alison R.; Trask, Stephen E.; Gering, Kevin L.

doi:10.1016/j.ensm.2021.10.011

Cited by 31 publications

(33 citation statements)

References 41 publications

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“…The R SEI and R B for the NMC811 cells, as summarized in Figure 2c and Figure 2e, closely follow the capacity fade trend observed in Figure 2a, commensurate to more SEI growth and electrolyte decomposition at the anode (see Figure S5 in the Supporting Information for additional explanation). [ 12,15,19,39,40 ] The NMC811 aging issues captured through the R CEI+CT impedance in Figure 2d, [ 41,42 ] as obtained from the mid‐frequency depressed semi‐circle in Figure S4 in the Supporting Information, show a gradual increase with cycling for 1C to 9C and 4.1 V charging conditions. This gradual and less severe increase in R CEI+CT in Figure 2d is starkly different from the NMC532 cells that showed sped up cathode degradation after about 400 cycles for the same fast‐charge cycling conditions, as shown in Figure 2 in ref.…”

Section: Resultsmentioning

confidence: 99%

“…[ 4–12 ] To solve the Li plating problem, researchers are exploring innovative materials, including electrolytes, electrode architectures, cell designs, charging conditions, and/or protocols. [ 8,11–15 ]…”

Section: Introductionmentioning

confidence: 99%

“…[4][5][6][7][8][9][10][11][12] To solve the Li plating problem, researchers are exploring innovative materials, including electrolytes, electrode architectures, cell designs, charging conditions, and/or protocols. [8,[11][12][13][14][15] While Li plating is directly identified as a critical concern during XFC, there is less distinct understanding on fast-charge aging effects in the cathode. It has been reported that cathode degradation issues such as particle cracking and surface degradation remain less visible during early cycling, but become more broadly visible As the battery industry shifts toward high Ni content cathodes, such as LiNi 0.8 Mn 0.1 Co 0.1 O 2 [NMC811], a complete understanding of the degradation mechanisms of NMC811 under extreme fast charging (XFC) (XFC, ≤10-15 min charging) conditions is needed.…”

Section: Introductionmentioning

confidence: 99%

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A Comprehensive Understanding of the Aging Effects of Extreme Fast Charging on High Ni NMC Cathode

Tanim

Yang

Finegan

et al. 2022

Advanced Energy Materials

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As the battery industry shifts toward high Ni content cathodes, such as LiNi0.8Mn0.1Co0.1O2 [NMC811], a complete understanding of the degradation mechanisms of NMC811 under extreme fast charging (XFC) (XFC, ≤10–15 min charging) conditions is needed. Such comprehensive understanding would identify the most critical materials gaps that need to be addressed for enabling XFC long‐life cells for electric vehicles. This study maps out the key aging mechanisms for NMC811 cycled at different XFC conditions (between 1C and 9C) for up to 1000 cycles. To acquire a fundamental understanding of utilization and degradation, cells are evaluated using a range of electrochemical techniques, and multimodal and multiscale microscopy techniques to quantify chemical, structural, and crystallographic degradation as a function of cycling conditions for the NMC cathode. When comparing NMC811 to NMC532, it is observed that NMC811 has a greater subsurface crystallographic degradation and displays a similar magnitude of subparticle cracking. However, the NMC811 maintains superior performance despite those advanced degradations. The superior cycle life performance is attributed to the NMC811 particles having radially oriented grains and improved transport properties. NMC811 shows between 4.6× and 3.15× reduction in capacity fade than NMC532 for charging rates between 4C (e.g., 15‐min charging) and 6C (10‐min charging).

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Comprehensive Understanding of the Aging Effects of Extreme Fast Charging on High Ni NMC Cathode

Tanim

Yang

Finegan

et al. 2022

Advanced Energy Materials

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“…Because of the favorable ionic conduction in the FDEE-LHCE and at the electrode/electrolyte interfaces, excellent high-rate performance of LMBs could be demonstrated (Figure 2b). 34,35 FDEE-LHCE has achieved unprecedented cell performance compared to the reported advanced electrolytes applied in NMC-based LMBs under high voltage (4.6 V and 4.7 V) and fast-charging conditions (up to 5.1 mA cm -2 ), as shown in Figure 2g, Figure S18-S21 and Table S2. Scanning electron microscope (SEM) was employed to characterize the morphology of the cathodes before and after cycling.…”

Section: Ultrahigh-voltage Lmb Performance and The Robust Cathode-ele...mentioning

confidence: 94%

Monofluoro-ether electrolyte design with reduced Li+-anion coordination enables fast-charging ultrahigh-voltage lithium metal batteries

Ruan

Tan

Chen

et al. 2022

Preprint

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Ether-based electrolytes are particularly useful for lithium metal batteries (LMBs) and have shown improved anodic stability with the high concentration design. Nevertheless, the vaunted anion-reinforced solvation in concentrated electrolytes has non-negligible adverse effect on ion conduction and battery rate performance. Here, we propose a new solvent design strategy of ether monofluorination to tune the Li+-anion interaction for fast-charging LMBs. With the highly polar monofluoro functional groups, the ether-based electrolyte not only exhibits excellent high oxidation stability due to the strong electron-withdrawing effect of F, but also has a greatly increased ionic conductivity because of reduced anion coordination. The unique solvation structure also enables the formation of robust and highly conductive interphases at both the Li anode and NMC811 surfaces. High Li CEs (~99.4%) and stable long-term cycling with low overpotential under ultrahigh current densities (10 mA cm-2) could be achieved for Li anode. Li||NMC811 cells exhibit outstanding cycling performance under ultrahigh cut-off voltages of 4.6 V and 4.7 V, or at high current densities (5.1 mA cm-2). This work provides critical insights into the ion-solvent interactions in the solvation complex and their profound influence on the battery electrochemical performances.

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“…The electrolyte design often must fulfill multiple, competing objectives within each application 22 , so optimal designs for rate-capability can differ from optimal designs for cycle-life. Relevant to this work, fast-charging battery electrolytes must be able to transport lithium ions to and into the negative electrode active material at high current rates (5–10 mA/cm 2 ), which is strongly associated with bulk transport properties (ionic conductivity, viscosity, diffusivity, cation transference number) and electrode interfacial kinetics (charge transfer impedance, desolvation dynamics) 23 , 24 .…”

Section: Introductionmentioning

confidence: 99%

Autonomous optimization of non-aqueous Li-ion battery electrolytes via robotic experimentation and machine learning coupling

et al. 2022

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Developing high-energy and efficient battery technologies is a crucial aspect of advancing the electrification of transportation and aviation. However, battery innovations can take years to deliver. In the case of non-aqueous battery electrolyte solutions, the many design variables in selecting multiple solvents, salts and their relative ratios make electrolyte optimization time-consuming and laborious. To overcome these issues, we propose in this work an experimental design that couples robotics (a custom-built automated experiment named "Clio”) to machine-learning (a Bayesian optimization-based experiment planner named "Dragonfly”). An autonomous optimization of the electrolyte conductivity over a single-salt and ternary solvent design space identifies six fast-charging non-aqueous electrolyte solutions in two work-days and forty-two experiments. This result represents a six-fold time acceleration compared to a random search performed by the same automated experiment. To validate the practical use of these electrolytes, we tested them in a 220 mAh graphite∣∣LiNi0.5Mn0.3Co0.2O2 pouch cell configuration. All the pouch cells containing the robot-developed electrolytes demonstrate improved fast-charging capability against a baseline experiment that uses a non-aqueous electrolyte solution selected a priori from the design space.

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Methodologies for Design, Characterization and Testing of Electrolytes that Enable Extreme Fast Charging of Lithium-ion Cells

Cited by 31 publications

References 41 publications

A Comprehensive Understanding of the Aging Effects of Extreme Fast Charging on High Ni NMC Cathode

A Comprehensive Understanding of the Aging Effects of Extreme Fast Charging on High Ni NMC Cathode

Monofluoro-ether electrolyte design with reduced Li+-anion coordination enables fast-charging ultrahigh-voltage lithium metal batteries

Autonomous optimization of non-aqueous Li-ion battery electrolytes via robotic experimentation and machine learning coupling

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