scholarly journals Quantification of Inactive Lithium and Solid Electrolyte Interphase (SEI) Species on Graphite Electrodes After Fast Charging

Author(s):  
Eric McShane ◽  
Andrew Colclasure ◽  
David Brown ◽  
Zachary M. Konz ◽  
Kandler Smith ◽  
...  

<p>Rapid charging of Li-ion batteries is limited by lithium plating on graphite anodes, whereby Li<sup>+</sup> ions are reduced to Li metal on the graphite particle surface instead of inserting between graphitic layers. Plated Li metal not only poses a safety risk due to dendrite formation, but also contributes to capacity loss due to the low reversibility of the Li plating/stripping process. Understanding when Li plating occurs and how much Li has plated is therefore vital to remedying these issues. We demonstrate a titration technique with a minimum detection limit of 20 nmol (5×10<sup>-4</sup> mAh) Li which is used to quantify inactive Li that remains on the graphite electrode after fast charging. Additionally, the titration is extended to quantify the total amount of solid carbonate species and lithium acetylide (Li<sub>2</sub>C<sub>2</sub>) within the solid electrolyte interphase (SEI). Finally, electrochemical modeling is combined with experimental data to determine the Li plating exchange current density (10 A/m<sup>2</sup>) and stripping efficiency (65%) of plated Li metal on graphite. These techniques provide a highly accurate measure of Li plating onset and quantitative insight into graphite SEI evolution during fast charge.</p>

2020 ◽  
Author(s):  
Eric McShane ◽  
Andrew Colclasure ◽  
David Brown ◽  
Zachary M. Konz ◽  
Kandler Smith ◽  
...  

<p>Rapid charging of Li-ion batteries is limited by lithium plating on graphite anodes, whereby Li<sup>+</sup> ions are reduced to Li metal on the graphite particle surface instead of inserting between graphitic layers. Plated Li metal not only poses a safety risk due to dendrite formation, but also contributes to capacity loss due to the low reversibility of the Li plating/stripping process. Understanding when Li plating occurs and how much Li has plated is therefore vital to remedying these issues. We demonstrate a titration technique with a minimum detection limit of 20 nmol (5×10<sup>-4</sup> mAh) Li which is used to quantify inactive Li that remains on the graphite electrode after fast charging. Additionally, the titration is extended to quantify the total amount of solid carbonate species and lithium acetylide (Li<sub>2</sub>C<sub>2</sub>) within the solid electrolyte interphase (SEI). Finally, electrochemical modeling is combined with experimental data to determine the Li plating exchange current density (10 A/m<sup>2</sup>) and stripping efficiency (65%) of plated Li metal on graphite. These techniques provide a highly accurate measure of Li plating onset and quantitative insight into graphite SEI evolution during fast charge.</p>


2020 ◽  
Vol 5 (6) ◽  
pp. 2045-2051 ◽  
Author(s):  
Eric J. McShane ◽  
Andrew M. Colclasure ◽  
David E. Brown ◽  
Zachary M. Konz ◽  
Kandler Smith ◽  
...  

2021 ◽  
Author(s):  
Le Anh Ma ◽  
Alexander Buckel ◽  
Leif Nyholm ◽  
Reza Younesi

Abstract Knowledge about capacity losses due to the formation and dissolution of the solid electrolyte interphase (SEI) layer in sodium-ion batteries (SIBs) is still limited. One major challenge in SIBs is the fact that the SEI generally contains more soluble species than the corresponding SEI layers formed in Li-ion batteries. By cycling carbon black electrodes against Na-metal electrodes, to mimic the SEI formation on negative SIB electrodes, this study studies the associated capacity losses in different carbonate electrolyte systems. Using electrochemical testing and synchrotron-based X-ray photoelectron (XPS) experiments, the capacity losses due to changes in the SEI layer and diffusion of sodium in the carbon black electrodes during open circuit pauses of 50 h, 30 h, 15 h and 5 h are investigated in nine different electrolyte systems. The different contributions to the open circuit capacity loss were determined using a new approach involving different galvanostatic cycling protocols. It is shown that the capacity loss depends on the interplay between the electrolyte chemistry and the thickness and stability of the SEI layer. The results show, that the Na-diffusion into the bulk electrode gives rise to a larger capacity loss than the SEI dissolution. Hence, Na-trapping effect is one of the major contribution in the observed capacity losses. Furthermore, the SEI formed in NaPF6-EC:DEC was found to become slightly thicker during 50 h pause, due to self-diffused deintercalation of Na from the carbon black structure coupled by further electrolyte reduction. On the other hand, the SEI in NaTFSI with the same solvent goes into dissolution during pause. The highest SEI dissolution rate and capacity loss was observed in NaPF6-EC:DEC (0.57 μAh/hpause) and the lowest in NaTFSI-EC:DME (0.15 μAh/hpause).


2009 ◽  
Vol 156 (4) ◽  
pp. A318 ◽  
Author(s):  
Ang Xiao ◽  
Li Yang ◽  
Brett L. Lucht ◽  
Sun-Ho Kang ◽  
Daniel P. Abraham

2016 ◽  
Vol 138 (25) ◽  
pp. 7918-7931 ◽  
Author(s):  
Alison L. Michan ◽  
Giorgio Divitini ◽  
Andrew J. Pell ◽  
Michal Leskes ◽  
Caterina Ducati ◽  
...  

2015 ◽  
Vol 162 (6) ◽  
pp. A892-A896 ◽  
Author(s):  
Hosang Park ◽  
Taeho Yoon ◽  
Youngjin Kim ◽  
Jae Gil Lee ◽  
Jongjung Kim ◽  
...  

Batteries ◽  
2019 ◽  
Vol 5 (4) ◽  
pp. 71 ◽  
Author(s):  
Martin Frankenberger ◽  
Madhav Singh ◽  
Alexander Dinter ◽  
Karl-Heinz Pettinger

This paper presents a comprehensive study of the influences of lamination at both electrode-separator interfaces of lithium-ion batteries consisting of LiNi1/3Mn1/3Co1/3O2 cathodes and graphite anodes. Typically, electrode-separator lamination shows a reduced capacity fade at fast-charging cycles. To study this behavior in detail, the anode and cathode were laminated separately to the separator and compared to the fully laminated and non-laminated state in single-cell format. The impedance of the cells was measured at different states of charge and during the cycling test up to 1500 fast-charging cycles. Lamination on the cathode interface clearly shows an initial decrease in the surface resistance with no correlation to aging effects along cycling, while lamination on both electrode-separator interfaces reduces the growth of the surface resistance along cycling. Lamination only on the anode-separator interface shows up to be sufficient to maintain the enhanced fast-charging capability for 1500 cycles, what we prove to arise from a significant reduction in growth of the solid electrolyte interface.


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