Aging in lithium-ion batteries: Model and experimental investigation of harvested LiFePO4 and mesocarbon microbead graphite electrodes

Zavalis, Tommy Georgios; Klett, Matilda; Kjell, Maria Hellqvist; Behm, Mårten; Lindström, Rakel Wreland; Lindbergh, Göran

doi:10.1016/j.electacta.2013.05.081

Cited by 93 publications

(86 citation statements)

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“…8 The potential and current distribution due to edge effects was previously examined in a comparison between internally and externally positioned reference electrodes of a similar set-up; 8 furthermore, the importance of electrode alignment and reference electrode position on electrodes measurements have been evaluated in different cell geometries. 1,2,4,8 The small distance of 50 μm between the electrodes in the present set-up makes the external RE measurement even more sensitive to electrode alignment compared to larger distances, for example compared to 600 μm used for measurements in, 28,29 and as also discussed in. 1,4 Furthermore, a precise electrode alignment is beyond experimental control in this set-up, and the over-or under-estimation of electrode ASI measured with the external Li-metal RE compared to the internal Li x Sn RE was seen to vary between cells.…”

Section: Resultsmentioning

confidence: 96%

Electrode Behavior RE-Visited: Monitoring Potential Windows, Capacity Loss, and Impedance Changes in Li_1.03(Ni_0.5Co_0.2Mn_0.3)_0.97O₂/Silicon-Graphite Full Cells

Klett

Gilbert

Trask

et al. 2016

J. Electrochem. Soc.

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120

110

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The capacity and power performance of lithium-ion battery cells evolve over time. The mechanisms leading to these changes can often be identified through knowledge of electrode potentials, which contain information about electrochemical processes at the electrodeelectrolyte interfaces. In this study we monitor electrode potentials within full cells containing a Li 1.03 (Ni 0.5 Co 0.2 Mn 0.3 ) 0.97 O 2 -based (NCM523) positive electrode, a silicon-graphite negative electrode, and an LiPF 6 -bearing electrolyte, with and without fluoroethylene carbonate (FEC) or vinylene carbonate (VC) additives. The electrode potentials are monitored with a Li-metal reference electrode (RE) positioned besides the electrode stack; changes in these potentials are used to examine electrode state-of-charge (SOC) shifts, material utilization, and loss of electrochemically active material. Electrode impedances are obtained with a Li x Sn RE located within the stack; the data display the effect of cell voltage and electrode SOC changes on the measured values after formation cycling and after aging. Our measurements confirm the beneficial effect of FEC and VC electrolyte additives in reducing full cell capacity loss and impedance rise after cycling in a 3.0-4.2 V range. Comparisons with data from a full cell containing a graphite-based negative highlight the consequences of including silicon in the electrode. Our observations on electrode potentials, capacity, and impedance changes on cycling are crucial to designing long-lasting, silicon-bearing, lithium-ion cells. As applications of lithium-ion systems expand beyond consumer electronics to the transportation and electricity storage markets, battery-cell longevity has become a primary barrier to widespread commercialization. While cells in smart phones are expected to function for about two years, energy storage units in electric vehicles are expected to maintain performance over a 10-15 year period. This performance is primarily defined by cell capacity and impedance characteristics, which change as electrode potentials and electrodeelectrolyte interfaces evolve over time. The knowledge of electrode potentials is very important for battery aging investigations because it can point to sources of performance degradation and, hence, lead to solutions that improve cell life. Such improvements are urgently needed for high-energy density cells, with silicon-containing-negative and layered-oxide-positive electrodes, being developed at Argonne National Laboratory as part of the U.S. DOE's Applied Battery Research (ABR) for Transportation program.The potentials of individual electrodes, such as that of a layeredoxide electrode, can be monitored in two-electrode cells by using a Li-metal counter electrode (CE) at low currents, or by using a CE with high surface areas, which reduce current densities and maintains a relatively stable potential. However, electrode potentials cannot be measured independently in commercial lithium-ion cells, which do not contain Li-metal. Yet aging investigations of ...

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Section: Resultsmentioning

confidence: 96%

Electrode Behavior RE-Visited: Monitoring Potential Windows, Capacity Loss, and Impedance Changes in Li_1.03(Ni_0.5Co_0.2Mn_0.3)_0.97O₂/Silicon-Graphite Full Cells

Klett

Gilbert

Trask

et al. 2016

J. Electrochem. Soc.

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120

110

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“…1a), this current is used to drive two electrochemical processes at the graphite electrode, according to I ch = I tr ch + I SE I [4] where I tr ch represents the charge transfer current used to facilitate Li + ion intercalation in the graphite electrode (Eq. 1) and I SE I is the current related to the SEI formation reactions (Eq.…”

Section: Sei Formation Mechanismmentioning

confidence: 99%

“…LFP batteries therefore combine a good cycling stability with excellent thermal stability and long lifespan. [1][2][3][4][5] The volume decreases only 6.8% 6 when all Li ( x = 1) is extracted and these small volumetric changes do not influence the structure of LiFePO 4 and FePO 4 . Favorably, it almost fully counterbalances the volumetric changes of the graphite electrode during Li (de)insertion.…”

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confidence: 99%

Modeling the SEI-Formation on Graphite Electrodes in LiFePO₄Batteries

Danilov

Zhang

et al. 2015

J. Electrochem. Soc.

113

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An advanced model is proposed, describing the capacity losses of C 6 /LiFePO 4 batteries under storage and cycling conditions. These capacity losses are attributed to the growth of a Solid Electrolyte Interface (SEI) at the surface of graphite particles in the negative electrode. The model assumes the existence of an inner and outer SEI layer. The rate determining step is considered to be electron tunneling through the inner SEI layer. The inner SEI layer grows much slower than the outer SEI layer. Another contribution to the degradation process is the exfoliation of SEI near the edges of graphite particles during discharging and the formation of new SEI induced by the volumetric changes during the subsequent charging. The model has been validated by storage and cycling experiments. The simulation results show that the capacity losses are dependent on the State-of-Charge (SoC), the storage time, cycle number and graphite particle size. The model can be used to predict both the calendar and cycling life of the Li-ion batteries. Li-ion batteries, based on the C 6 /LiFePO 4 chemistry, attracts nowadays much attention for application in, for example, electric vehicles due to the excellent cycling stability of the LiFePO 4 electrode. The main electrochemical storage reactions of this battery type can be represented byDuring charging electrons and Li + ions are extracted from the LiFePO 4 (0 ≤ x ≤ 1) electrode and flow into the graphite electrode. The reverse reactions take place during discharging. The structure of LiFePO 4 (LFP) is highly robust due to the strong bonding between the P and O atoms. LFP batteries therefore combine a good cycling stability with excellent thermal stability and long lifespan.1-5 The volume decreases only 6.8% 6 when all Li ( x = 1) is extracted and these small volumetric changes do not influence the structure of LiFePO 4 and FePO 4 . Favorably, it almost fully counterbalances the volumetric changes of the graphite electrode during Li (de)insertion.Due to these favorable properties, the capacity losses caused by the LFP cathode are generally assumed to be negligible. Furthermore, Broussely et al. showed that the capacity of the graphite electrode can be fully recovered even after more than 1 year storage under 'floating' conditions at 60• C, demonstrating that the stability of the carbon electrode is also excellent.7 However, capacity losses are still found in LFP batteries. It is generally accepted, that the formation of a Solid Electrolyte Interface (SEI) is one of the main reasons for the capacity losses of graphite-based Li-ion batteries, especially under moderate conditions during the initial stages of aging.The SEI plays a dual-role in the performance of Li-ion batteries. On the one hand, it protects the negative electrode from solvent cointercalation, preventing exfoliation of the graphene layers. On the other hand, it consumes cyclable lithium inside the battery, which is therefore no longer available for the energy storage process and hence * Electrochemical Society Active Member...

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“…A decisive requirement for the design of the experimental setup was the shape of the current ripple. As demonstrated in [10], for frequencies above 1 kHz, inductive effects in the current collectors and leads become dominant. This means that the exact shape of the ripple is therefore expected to have minimal effect on the aging of the cells.…”

Section: Experimental Setup Requirementsmentioning

confidence: 98%

Design aspects of an experimental setup for investigating current ripple effects in lithium-ion battery cells

Soares

Bessman

Wallmark

et al. 2015

2015 17th European Conference on Power Electronics and Applications (EPE'15 ECCE-Europe)

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This paper describes an experimental setup for investigating the effects of current ripple on lithium-ion battery cells. The experimental setup is designed so that twelve li-ion cells can be simultaneously tested in a controlled environment. The experimental setup allows for a wide range of current ripple in terms of frequency and amplitude. Additionally, the quantification of the current ripple effects such as the aging of li-ion cells implies that a precise measurement system has to be designed which also are discussed in the paper.

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Aging in lithium-ion batteries: Model and experimental investigation of harvested LiFePO4 and mesocarbon microbead graphite electrodes

Cited by 93 publications

References 50 publications

Electrode Behavior RE-Visited: Monitoring Potential Windows, Capacity Loss, and Impedance Changes in Li_1.03(Ni_0.5Co_0.2Mn_0.3)_0.97O₂/Silicon-Graphite Full Cells

Electrode Behavior RE-Visited: Monitoring Potential Windows, Capacity Loss, and Impedance Changes in Li_1.03(Ni_0.5Co_0.2Mn_0.3)_0.97O₂/Silicon-Graphite Full Cells

Modeling the SEI-Formation on Graphite Electrodes in LiFePO₄Batteries

Design aspects of an experimental setup for investigating current ripple effects in lithium-ion battery cells

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Aging in lithium-ion batteries: Model and experimental investigation of harvested LiFePO4 and mesocarbon microbead graphite electrodes

Cited by 93 publications

References 50 publications

Electrode Behavior RE-Visited: Monitoring Potential Windows, Capacity Loss, and Impedance Changes in Li1.03(Ni0.5Co0.2Mn0.3)0.97O2/Silicon-Graphite Full Cells

Electrode Behavior RE-Visited: Monitoring Potential Windows, Capacity Loss, and Impedance Changes in Li1.03(Ni0.5Co0.2Mn0.3)0.97O2/Silicon-Graphite Full Cells

Modeling the SEI-Formation on Graphite Electrodes in LiFePO4Batteries

Design aspects of an experimental setup for investigating current ripple effects in lithium-ion battery cells

Contact Info

Product

Resources

About

Electrode Behavior RE-Visited: Monitoring Potential Windows, Capacity Loss, and Impedance Changes in Li_1.03(Ni_0.5Co_0.2Mn_0.3)_0.97O₂/Silicon-Graphite Full Cells

Electrode Behavior RE-Visited: Monitoring Potential Windows, Capacity Loss, and Impedance Changes in Li_1.03(Ni_0.5Co_0.2Mn_0.3)_0.97O₂/Silicon-Graphite Full Cells

Modeling the SEI-Formation on Graphite Electrodes in LiFePO₄Batteries