Abstract
Electrolyte additives are known to improve the performance of lithium-ion cells. In this work we examine the performance of Li1.03Ni0.5Mn0.3Co0.3O2-graphite (NMC532/Gr) cells containing combinations of lithium bis(oxalate)borate (LiBOB), vinylene carbonate (VC), trivinylcyclotriboroxane (tVCBO), prop-1-ene-1,3-sultone (PES), phenyl boronic acid ethylene glycol ester (PBE), tris(trimethylsilyl) phosphite (TMSPi), triethyl phosphite (TEPi), and lithium difluoro(oxalate)borate (LiDFOB) added to our baseline (1.2 M LiPF6 in EC:EMC, 3:7 w/w) electrolyte. In order to rank performance of the various electrolytes, we developed two separate figures of merit (FOM), which are based on the energy retention and power retention of the cells. Using these two metrics in conjunction, we show that only one of the fifteen electrolyte formulations tested significantly outperforms the baseline electrolyte: this electrolyte contains the 0.25 wt% tVCBO + 1 wt% TMSPi additive mix. Little correlation was observed between the FOMs for energy retention and power retention, which indicates that the mechanisms that govern these performance parameters are likely independent of each other. Our FOM approach has general applicability and can be used to develop electrolyte and electrode formulations that prolong the life of lithium-ion batteries.
Original language | English |
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Pages (from-to) | 201-209 |
Number of pages | 9 |
Journal | Journal of Power Sources |
Volume | 365 |
DOIs | |
State | Published - 2017 |
Externally published | Yes |
Funding
The lead authors A.T., C.P., and J.A.G. contributed equally to this article. We gratefully acknowledge support from the U.S. Department of Energy's Vehicle Technologies Program (DOE-VTP) , specifically from Peter Faguy and Dave Howell. The electrodes in this article were fabricated at Argonne's Cell Analysis, Modeling and Prototyping (CAMP) Facility , which is supported within the core funding of the Applied Battery Research (ABR) for Transportation Program. We are grateful to the HEHV team members for their suggestions, especially to S. Trask, B. Polzin, A. Jansen, J. Croy, Z. Zhang, I. Bloom, and D. Dees.
Keywords
- Capacity fade
- Energy density
- Full cells
- Impedance rise
- Lithium-ion
- Power density