Optimization of Na-Ion Battery Systems Based on Polyanionic or Layered Positive Electrodes and Carbon Anodes

Dugas, Romain; Zhang, Biao; Rozier, Patrick; Tarascon, Jean‐Marie

doi:10.1149/2.0051605jes

Cited by 77 publications

(83 citation statements)

References 18 publications

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“…16 Turning to the Na/C half cells, the addition of FEC leads to a slightly higher irreversible capacity that reaches 72 mA h g −1 instead of 61 mA h g −1 for FEC-free electrolyte, in agreement with a previous report. 17 A more prominent difference regarding the first discharge curve is the feature at 650 mV vs. Na + /Na in presence of FEC ( Figure 5d) whereas a smooth voltage decrease is observed in absence of FEC. Beyond this feature the curve obtained with FEC keeps shifting toward lower potentials suggesting an impedance increase.…”

Section: Resultsmentioning

confidence: 91%

“…The fact that the voltage drops are not observed for cells without FEC while for such cells the switching from Na plated to Na bulk also occurs owing to the poor efficiency of the plating/stripping process (33-55%) 3,17 seems to dismiss the first hypothesis. To confirm the validity of the second, NVPF/stainless steel cells were left at OCV in presence of Na plated on the stainless steel disk.…”

Section: Resultsmentioning

confidence: 99%

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Na Reactivity toward Carbonate-Based Electrolytes: The Effect of FEC as Additive

Dugas

Ponrouch

Gachot

et al. 2016

J. Electrochem. Soc.

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161

127

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Na-ion batteries have regained attention because they offer sustainability advantages over the Li-ion technology, hence their interest for massive electrochemical storage. Although the Na-ion electrochemistry is analogous to that of the Li-ion concept, there are a few notable differences such as the stability of carbonated-based electrolytes toward the Li or Na metal anodes. Herein we report on the positive effect of FEC as electrolyte additive on the efficiency of Na-half cells which unfortunately comes with a side effect involving the sudden onset of polarization during discharge at unpredictable capacity values. We show that these anomalies, associated to an inefficient plating-stripping at the sodium metal anode, do not appear in full Na-ion cells. Therefore, FEC-based electrolytes are not the panacea and alternative additives must be sought to enable building of reliable half cells with metal anodes. After years of shy consideration, Na-ion batteries are currently attracting increasing attention as alternative to Li-ion batteries. Their long-sight interest resides in the absence of lithium, for which the global amount and localization of the sources brings concern in a context where electric vehicles and grid storage have to be massively developed. On a shorter time scale, Na-ion batteries benefit from the lower cost of the Na-based precursors and the possible use of Al instead of Cu as anode current collector.Today, steady progress in Na-ion batteries is being achieved. 1The technology being similar in its principle to Li-ion batteries, its development massively benefits from the knowledge accumulated with the latter. However, significant differences between Liand Na-based systems 2 prevent direct transposition of all the chemical tricks/techniques commonly used for lithium. Just like for their Li-based counterpart, the development of Na-ion battery systems requires a reliable setup to test each electrode material independently prior to the assembly of full cells. While metallic Li is a stable counter-electrode acting as reference to survey Li-ion active materials in a two-electrode cell, concerns have risen regarding the suitability of Na anodes.3,4 Indeed they show much higher impedance than Li in conventional carbonate-based electrolytes and a non stable SEI.FluoroEthylene Carbonate, FEC, has been a popular electrolyte additive in Na-ion batteries after it was shown that it can improve the efficiency and stability of half cells 5 while introducing anomalies in the voltage curve which have been so far unexplained. As a film-forming additive, 6 it was proposed that its beneficial effect was due to the formation of a more stable SEI on hard carbon. However, in the case of some hard C electrodes, the performance and cyclability were actually lower in half-cells with FEC than without additive.7 FEC also induces electrochemical features in a 2-electrode measurement vs. Na, namely the presence of a voltage drop in the reduction sweep as can be seen in several plots in the literature. 5,[8][9][10][11] In this w...

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Section: Resultsmentioning

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Na Reactivity toward Carbonate-Based Electrolytes: The Effect of FEC as Additive

Dugas

Ponrouch

Gachot

et al. 2016

J. Electrochem. Soc.

Self Cite

161

127

View full text Add to dashboard Cite

show abstract

“…

counterparts, hence offering practical interest for grid applications where capabilities for smoothening fluctuations and low cost are the overriding factors. [8][9][10][11] We have recently benchmarked such Na-ion full cells having sodium layered oxide electrodes with either O3 or P2 structures and TM/TM′ of different nature against Na 3 V 2 (PO 4 ) 2 F 3 /HC cells. [8][9][10][11] We have recently benchmarked such Na-ion full cells having sodium layered oxide electrodes with either O3 or P2 structures and TM/TM′ of different nature against Na 3 V 2 (PO 4 ) 2 F 3 /HC cells.

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confidence: 99%

Reaching the Energy Density Limit of Layered O3‐NaNi_0.5Mn_0.5O₂ Electrodes via Dual Cu and Ti Substitution

Wang

Mariyappan

Vergnet

et al. 2019

Advanced Energy Materials

149

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counterparts, hence offering practical interest for grid applications where capabilities for smoothening fluctuations and low cost are the overriding factors. [1][2][3][4][5][6][7] Most of the Na-ion systems demonstrated till now use hard carbon (HC) as common negative electrode and either sodium layered oxides (Na x TMO 2 , 0 < x ≤ 1, TM = transition metals) or polyanionic compounds (Na 3 V 2 (PO 4 ) 2 F 3 ) as positive electrodes. [8][9][10][11] We have recently benchmarked such Na-ion full cells having sodium layered oxide electrodes with either O3 or P2 structures and TM/TM′ of different nature against Na 3 V 2 (PO 4 ) 2 F 3 /HC cells. [12] Whatever the figures of merit we have checked, such as specific energy, cyclability as well as rate capability, the 3D Na 3 V 2 (PO 4 ) 2 F 3 (NVPF) phase outperforms the layered phases, irrespective of its high molecular weight and modest capacity (128 mAh g −1 , equivalent to 2 Na + exchange). [13] Moreover, sodium based layered oxides reported so far, whatever O or P-type structures, suffer from low redox potential, limited reversible capacity versus carbon in Na-ion full cells (hardly 50% of their theoretical capacity), Na-driven structural instability and moisture sensitivity. [14,15] So how long will this supremacy of NVPF last?To compete with NVPF, it is important to design sodium layered oxides, which can reversibly release and uptake Na + ions Although being less competitive energy density-wise, Na-ion batteries are serious alternatives to Li-ion ones for applications where cost and sustainability dominate. O3-type sodium layered oxides could partially overcome the energy limitation, but their practical use is plagued by a reaction process that enlists numerous phase changes and volume variations while additionally being moisture sensitive. Here, it is shown that the double substitution of Ti for Mn and Cu for Ni in O3-NaNi 0.5 − y Cu y Mn 0.5 − z Ti z O 2 can alleviate most of these issues. Among this series, electrodes with specific compositions are identified that can reversibly release and uptake ≈0.9 sodium per formula unit via a smooth voltage-composition profile enlisting minor lattice volume changes upon cycling as opposed to ΔV/V≈23% in the parent NaNi 0.5 Mn 0.5 O 2 while showing a greater resistance against moisture. The positive attributes of substitution are rationalized by structure considerations supported by density functional theory (DFT) calculations. Electrodes with sustained capacities of ≈180 mAh g −1 are successfully implemented into 18 650 Na-ion cells having greater performances, energy density-wise (≈250 Wh L −1 ), than today's Na 3 V 2 (PO 4 ) 2 F 3 /HC Na-ion technology which excels in rate capabilities. These results constitute a step forward in increasing the practicality of Na-ion technology with additional opportunities for applications in which energy density prevails over rate capability.

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“…5% fluoroethylene carbonate (FEC) is used as additives to stabilize Na metal and also help to establish a stable SEI. [26] Around 2.7…”

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Microsized Sn as Advanced Anodes in Glyme‐Based Electrolyte for Na‐Ion Batteries

et al. 2016

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Optimization of Na-Ion Battery Systems Based on Polyanionic or Layered Positive Electrodes and Carbon Anodes

Cited by 77 publications

References 18 publications

Na Reactivity toward Carbonate-Based Electrolytes: The Effect of FEC as Additive

Na Reactivity toward Carbonate-Based Electrolytes: The Effect of FEC as Additive

Reaching the Energy Density Limit of Layered O3‐NaNi_0.5Mn_0.5O₂ Electrodes via Dual Cu and Ti Substitution

Microsized Sn as Advanced Anodes in Glyme‐Based Electrolyte for Na‐Ion Batteries

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Optimization of Na-Ion Battery Systems Based on Polyanionic or Layered Positive Electrodes and Carbon Anodes

Cited by 77 publications

References 18 publications

Na Reactivity toward Carbonate-Based Electrolytes: The Effect of FEC as Additive

Na Reactivity toward Carbonate-Based Electrolytes: The Effect of FEC as Additive

Reaching the Energy Density Limit of Layered O3‐NaNi0.5Mn0.5O2 Electrodes via Dual Cu and Ti Substitution

Microsized Sn as Advanced Anodes in Glyme‐Based Electrolyte for Na‐Ion Batteries

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Reaching the Energy Density Limit of Layered O3‐NaNi_0.5Mn_0.5O₂ Electrodes via Dual Cu and Ti Substitution