| 1. |
- Bergfelt, Andreas, et al.
(författare)
-
A Mechanical Robust yet highly Conductive Diblock Copolymer-based Solid Polymer Electrolyte for Room Temperature Structural Battery Applications
- 2020
-
Ingår i: ACS Applied Polymer Materials. - : American Chemical Society (ACS). - 2637-6105. ; 2:2, s. 939-948
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper we present a solid polymer electrolyte (SPE) that uniquely combines ionic conductivity and mechanical robustness. This is achieved with a diblock copolymer poly(benzyl methacrylate)-poly(ε-caprolactone-r-trimethylene carbonate). The SPE with 16.7 wt% lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) showed the highest ionic conductivity (9.1×10−6 S cm−1 at 30 °C) and apparent transference number (T+) of 0.64 ± 0.04. Due to the employment of the benzyl methacrylate hard-block, this SPE is mechanically robust with a storage modulus (E') of 0.2 GPa below 40 °C, similar to polystyrene, thus making it a suitable material also for load-bearing constructions. The cell Li|SPE|LiFePO4 is able to cycle reliably at 30 °C for over 300 cycles. The promising mechanical properties, desired for compatibility with Li-metal, together with the fact that BCT is a highly reliable electrolyte material makes this SPE an excellent candidate for next-generation all-solid-state batteries.
|
|
| 2. |
- Bergfelt, Andreas, et al.
(författare)
-
d8-poly(methyl methacrylate)-poly[(oligo ethylene glycol) methyl ether methacrylate] tri-block-copolymer electrolytes : Morphology, conductivity and battery performance
- 2017
-
Ingår i: Polymer. - : Elsevier BV. - 0032-3861 .- 1873-2291. ; 131, s. 234-242
-
Tidskriftsartikel (refereegranskat)abstract
- A series of deuterated tri-block copolymers with the general structure d(8)-PMMA-POEGMA-d(8)-PMMA, with variation in d(8)-PMMA chain length, were synthesized using sequential controlled radical polymerization (ATRP). Solid polymer electrolytes (SPEs) were produced by blending tri-block copolymers and lithium bis(trifluoro methylsulfonate) (LiTFSI). Small-angle neutron scattering (SANS) was used to study the bulk morphology of the deuterated tri-block copolymer electrolyte series at 25 degrees C, 60 degrees C and 95 degrees C. The lack of a second T-g in DSC analysis together with modelling with the random phase approximation model (RPA) confirmed that the electrolytes are in the mixed state, with negative Flory-Huggins interaction parameters. AC impedance spectroscopy was used to study the ionic conductivity of the SPE series in the temperature interval 30 degrees C-90 degrees C, and a battery device was constructed to evaluate a 25 wt% d(8)-PMMA electrolyte. The Li | SPE | LiFePO4 cell cycled at 60 degrees C, giving a discharge capacity of 120 mAh g(-1), while cyclic voltammetry showed that the SPE was stable at 60 degrees C.
|
|
| 3. |
- Bergfelt, Andreas, et al.
(författare)
-
Mechanically Robust and Highly Conductive Di-Block Copolymers as Solid Polymer Electrolytes for Room Temperature Li-ion Batteries
- 2018
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Alternative solid polymer electrolytes (SPEs) hosts to the archetype poly(ethylene oxide) are gaining attention thanks to their appealing properties, such as higher cation transport number, thermal stability and electrochemical stability [1]. In addition, high mechanical stability is required in order to integrate easy-to-use materials into flexible or ‘structural’ batteries [2, 3]. In this work, a solid polymer electrolyte (SPE) featuring high ionic conductivity and mechanical robustness at room temperature is presented. The SPE consists of a di-block copolymer, poly(benzyl methacrylate)-poly(ε-caprolactone-r-trimethylene carbonate) (BCT), mixed with different loadings of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The highest ionic conductivity achieved for these SPEs was found with 16.7 wt% LiTFSI loading (BCT17), reaching 9.1 x 10-6 S cm-1 at 30 °C. The limited current fraction (F+) for the BCT17 electrolyte was calculated to be 0.64 with the Bruce-Vincent method. Furthermore, dynamic mechanical analysis showed a storage modulus (E’) of 0.2 GPa below 40 °C and 1 MPa above 50 °C. These results indicate that BCT with LiTFSI is a competitive electrolyte, combining high ionic conductivity and modulus at ambient temperatures. LiFePO4|BCT17|Li half-cells showed good cycling performance at 60 °C. At 30 °C, where the SPE possessed significantly higher modulus, decent cell performance could still be achieved after several optimization steps. These included incorporating a SPE as binder, and infiltration cast the SPE on the electrode to maximize the contact between both components, thereby improving the interfacial contact and decreasing the cell resistance and overpotential when cycling the battery device. References[1] J. Mindemark, M.J. Lacey, T. Bowden, D. Brandell. Prog Polym Sci, (2018). DOI: 10.1016/j.progpolymsci.2017.12.004.[2] J.F. Snyder, R.H. Carter, E.D. Wetzel. Chem Mater, 19 (2007) 3793-801.[3] W.S. Young, W.F. Kuan, Thomas H. Epps. J Polym Sci, Part B: Polym Phys, 52 (2014) 1-16.
|
|
| 4. |
- Brant, William, et al.
(författare)
-
Method of producing a sodium iron(II)-hexacyanoferrate(II) material
- 2018
-
Patent (populärvet., debatt m.m.)abstract
- The present invention relates to a method of producing a sodium iron(ll)- hexacyanoferrate(ll) (Na2-xFe[Fe(CN)6].mH2O), where x is < 0.4) material commonly referred to as Prussian White. The method comprises the steps of acid decomposition of Na4Fe(CN)6.10H2O to a powder of Na2-xFe[Fe(CN)6].mH2O, drying and enriching the sodium content in the Na2-xFe[Fe(CN)6].mH2O powder by mixing the powder with a saturated or supersaturated solution of a reducing agent containing sodium in dry solvent under an inert gas. The steps of acid decomposition and enriching the sodium content are performed under non-hydrothermal conditions.
|
|
| 5. |
- Brant, William, et al.
(författare)
-
Selective Control of Composition in Prussian White for Enhanced Material Properties
- 2019
-
Ingår i: Chemistry of Materials. - : AMER CHEMICAL SOC. - 0897-4756 .- 1520-5002. ; 31:18, s. 7203-7211
-
Tidskriftsartikel (refereegranskat)abstract
- Sodium-ion batteries based on Prussian blue analogues (PBAs) are ideal for large-scale energy storage applications due to the ability to meet the huge volumes and low costs required. For Na2-xFe[Fe(CN)(6)](1-y)center dot zH(2)O, realizing its commercial potential means fine control of the concentration of sodium, Fe(CN)(6) vacancies, and water content. To date, there is a huge variation in the literature of composition leading to variable electrochemical performance. In this work, we break down the synthesis of PBAs into three steps for controlling the sodium, vacancy, and water content via an inexpensive, scalable synthesis method. We produce rhombohedral Prussian white Na1.88(5)Fe[Fe-(CN)(6)]center dot 0.18(9)H2O with an initial capacity of 158 mAh/g retaining 90% capacity after 50 cycles. Subsequent characterization revealed that the increased polarization on the 3 V plateau is coincident with a phase transition and reduced utilization of the high-spin Fe(III)/Fe(II) redox couple. This reveals a clear target for subsequent improvements of the material to boost long-term cycling stability. These results will be of great interest for the myriad of applications of PBAs, such as catalysis, magnetism, electrochromics, and gas sorption.
|
|
| 6. |
- Buckel, Alexander, et al.
(författare)
-
Importance of First Cycle Conditions on the Electrochemical Performance of Hard Carbon and Prussian White Based Sodium-Ion Batteries Using Fire Resistant, Fluorine-Free Electrolyte
- 2024
-
Ingår i: Batteries & Supercaps. - : John Wiley & Sons. - 2566-6223. ; 7:2
-
Tidskriftsartikel (refereegranskat)abstract
- Electrolytes based on sodium bis(oxolato)borate (NaBOB) in organophosphates (trimethyl phosphate and triethyl phosphate (TEP)) have shown promise in sodium-ion batteries when compared to conventional electrolytes in that they are fire resistant, fluorine-free and are of lower toxicity. However, these electrolytes tend to exhibit low initial Coulombic efficiency and high overpotentials. We have here demonstrated that NaBOB in TEP can be used in cells with near-commercial capacity loadings. Furthermore, we have shown that formation cycle conditions have a significant positive effect on the cell performance in these higher mass loading cells, and that modification of the formation cycle conditions can be used to increase the capacity retention, lower the overpotentials, and as such increase the rate capability. The viability of optimized formation protocols was also demonstrated in scaled up prototype cells. Formation cycling: In this article we present a solution to the poor cyclability of non-flammable sodium bis(oxolato)borate (NaBOB) in triethyl phosphate (TEP) electrolyte. By developing a formation cycle specific to this NaBOB in TEP electrolyte, we are able to cycle a 4.5 Ah full cell with high mass loading electrodes to beyond 900 cycles before reaching 80 % state of health.image
|
|
| 7. |
- Colbin, Simon, et al.
(författare)
-
A Halogen‐Free and Flame‐Retardant Sodium Electrolyte Compatible with Hard Carbon Anodes
- 2021
-
Ingår i: Advanced Materials Interfaces. - : John Wiley & Sons. - 2196-7350. ; 8:23
-
Tidskriftsartikel (refereegranskat)abstract
- For sodium-ion batteries, two pressing issues concerning electrolytes are flammability and compatibility with hard carbon anode materials. Non-flammable electrolytes that are sufficiently stable against hard carbon have—to the authors’ knowledge—previously only been obtained by either the use of high salt concentrations or additives. Herein, the authors present a simple, fluorine-free, and flame-retardant electrolyte which is compatible with hard carbon: 0.38 m sodium bis(oxalato)borate (NaBOB) in triethyl phosphate (TEP). A variety of techniques are employed to characterize the physical properties of the electrolyte, and to evaluate the electrochemical performance in full-cell sodium-ion batteries. The results reveal that the conductivity is sufficient for battery operation, no significant self-discharge occurs, and a satisfactory passivation is enabled by the electrolyte. In fact, a mean discharge capacity of 107 ± 4 mAh g−1 is achieved at the 1005th cycle, using Prussian white cathodes and hard carbon anodes. Hence, the studied electrolyte is a promising candidate for use in sodium-ion batteries.
|
|
| 8. |
- Gond, Ritambhara, et al.
(författare)
-
Non-flammable liquid electrolytes for safe batteries
- 2021
-
Ingår i: Materials Horizons. - : Royal Society of Chemistry. - 2051-6347 .- 2051-6355. ; 8:11, s. 2913-2928
-
Tidskriftsartikel (refereegranskat)abstract
- With continual increments in energy density gradually boosting the performance of rechargeable alkali metal ion (e.g. Li+, Na+, K+) batteries, their safe operation is of growing importance and needs to be considered during their development. This is essential, given the high-profile incidents involving battery fires as portrayed by the media. Such hazardous events result from exothermic chemical reactions occurring between the flammable electrolyte and the electrode material under abusive operating conditions. Some classes of non-flammable organic liquid electrolytes have shown potential towards safer batteries with minimal detrimental effect on cycling and, in some cases, even enhanced performance. This article reviews the state-of-the-art in non-flammable liquid electrolytes for Li-, Na- and K-ion batteries. It provides the reader with an overview of carbonate, ether and phosphate-based organic electrolytes, co-solvated electrolytes and electrolytes with flame-retardant additives as well as highly concentrated and locally highly concentrated electrolytes, ionic liquids and inorganic electrolytes. Furthermore, the functionality and purpose of the components present in typical non-flammable mixtures are discussed. Moreover, many non-flammable liquid electrolytes are shown to offer improved cycling stability and rate capability compared to conventional flammable liquid electrolytes.
|
|
| 9. |
- Hedman, Jonas, et al.
(författare)
-
Fiber Optic Sensor for Detection of Sodium Plating in Sodium-ion Batteries
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Optical fiber sensors integrated into sodium-ion batteries could provide a battery management system (BMS) with information to identify early warning signs of plating, preventing catastrophic failure and maintaining safe operation during fast charging. This work shows the possibility to directly detect plating of sodium metal in electrochemical cells by means of operando fiber optic evanescent wave (FOEW) spectroscopy. The results include measurements with FOEW sensors on bare copper substrates as well as on hard carbon anodes during operation in both half- and full-cell configurations. Full-cells using hard carbon anodes and Prussian white cathodes with high areal capacities (>1.5 mAh cm−2) and integrated FOEW sensors are shown to cycle well in pouch cells. The results also include measurements to demonstrate plating on hard carbon during sodiation at different rates.
|
|
| 10. |
- Hedman, Jonas, et al.
(författare)
-
Fiber Optic Sensors for Detection of Sodium Plating in Sodium-Ion Batteries
- 2022
-
Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 5:5, s. 6219-6227
-
Tidskriftsartikel (refereegranskat)abstract
- Optical fiber sensors integrated into sodium-ion batteries could provide a battery management system (BMS) with information to identify early warning signs of plating, preventing catastrophic failure and maintaining safe operation during fast charging. This work shows the possibility of directly detecting plating of sodium metal in electrochemical cells by means of operando fiber optic evanescent wave (FOEW) spectroscopy. The results include measurements with FOEW sensors on bare copper substrates as well as on hard carbon anodes during operation in both half- and full-cell configurations. Full cells using hard carbon anodes and Prussian white cathodes with high areal capacities (>1.5 mAh cm(-2)) and integrated FOEW sensors are shown to cycle well in pouch cells. The results also include measurements to demonstrate plating on hard carbon during sodiation at different rates.
|
|
