In this work we present a very simple preparation procedure of a poly(ethylene oxide) (PEO)-based crosslinked polymer electrolyte (XPE) for application in sodium-ion batteries (NIBs). The polymer ...electrolyte, containing NaClO4 as Na+ source, is prepared by rapid, energy saving, solvent-free photopolymerization technique, in a single step. Thermal, mechanical, morphological and electrochemical properties of the resulting XPE are thoroughly investigated. The highly ionic conducting (>1 mS cm−1 at 25 °C) polymer electrolyte is used in a lab-scale sodium cell with nanostructured TiO2 working electrode. The obtained results in terms of ambient temperature cycling behaviour (stable specific capacity of about 250 mAh g−1 at 0.1 mA cm−2 and overall remarkable stability, for a quasi-solid state Na polymer cell, upon very long term cycling exceeding 1000 reversible cycles at 0.5 mA cm−2 corresponding to > 5000 h of continuous operation) demonstrate the promising prospects of this novel XPE to be implemented in the next-generation NIBs conceived for large-scale energy storage systems, such as those connected to photovoltaic and wind factories.
•A solvent-free photocrosslinked PEO-based polymer electrolyte for sodium-ion batteries.•The electrolyte shows excellent thermal properties (Tg = −63 °C, TGA peak > 100 °C).•Ionic conductivity exceeding 1 mS cm−1 at 25 °C and ESW as wide as 4.7 V vs. Na+/Na.•TiO2-based lab-scale cells delivered stable specific capacity of 250 mAh g−1.•A very long-term cycling test exceeding 5200 h was carried out.
Polyethylene oxide (PEO)-based solid polymer electrolytes (SPEs) typically reveal a sudden failure in Li metal cells particularly with high energy density/voltage positive electrodes, e.g. LiNi
Mn
Co
...O
(NMC622), which is visible in an arbitrary, time - and voltage independent, "voltage noise" during charge. A relation with SPE oxidation was evaluated, for validity reasons on different active materials in potentiodynamic and galvanostatic experiments. The results indicate an exponential current increase and a potential plateau at 4.6 V vs. Li|Li
, respectively, demonstrating that the main oxidation onset of the SPE is above the used working potential of NMC622 being < 4.3 V vs. Li|Li
. Obviously, the SPE│NMC622 interface is unlikely to be the primary source of the observed sudden failure indicated by the "voltage noise". Instead, our experiments indicate that the Li | SPE interface, and in particular, Li dendrite formation and penetration through the SPE membrane is the main source. This could be simply proven by increasing the SPE membrane thickness or by exchanging the Li metal negative electrode by graphite, which both revealed "voltage noise"-free operation. The effect of membrane thickness is also valid with LiFePO
electrodes. In summary, it is the cell set-up (PEO thickness, negative electrode), which is crucial for the voltage-noise associated failure, and counterintuitively not a high potential of the positive electrode.
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•A novel cellulosic polymer electrolyte is proposed for Na-ion batteries.•Green functional biopolymer is present both in solid electrolyte and electrode.•Optimised ...electrode/electrolyte interface is obtained.•Stable cycling in Na/TiO2 and Na/NaFePO4 cells at 55°C.•A simple, cheap and water-based approach for solid Na-ion polymer cells.
In the present work, a novel pyranose ring laden polymer electrolyte is proposed for all solid Na-ion secondary cells that can operate at moderate temperatures. The prepared fully solid polymer electrolyte film is based on a classic polyethylene oxide (PEO) backbone, homogeneously blended with sodium carboxymethyl cellulose (Na-CMC) and sodium perchlorate. The favourable use of Na-CMC as electrode binder as well as electrolyte additive is evaluated, which would enhance the pathways for forming an optimised electrode/electrolyte interface. The promising prospects of the newly elaborated hybrid electrolyte are investigated by means of galvanostatic charge/discharge cycling in lab-scale cell with TiO2-based or NaFePO4-based working electrodes.
Polymer electrolytes have been proposed as replacement for conventional liquid electrolytes in lithium-ion batteries (LIBs) due to their intrinsic enhanced safety. Nevertheless, the power delivery of ...these materials is limited by the concentration gradient of the lithium salt. Single-ion conducting polyelectrolytes represent the ideal solution since their nature prevents polarization phenomena. Herein, the preparation of a new family of single-ion conducting block copolymer polyelectrolytes via reversible addition–fragmentation chain transfer polymerization technique is reported. These copolymers comprise poly(lithium 1-3-(methacryloyloxy)propylsulfonyl-1-(trifluoromethylsulfonyl)imide) and poly(ethylene glycol) methyl ether methacrylate blocks. The obtained polyelectrolytes show low T g values in the range of −61 to 0.6 °C, comparatively high ionic conductivity (up to 2.3 × 10–6 and 1.2 × 10–5 S cm–1 at 25 and 55 °C, respectively), wide electrochemical stability (up to 4.5 V versus Li+/Li), and a lithium-ion transference number close to unity (0.83). Owing to the combination of all mentioned properties, the prepared polymer materials were used as solid polyelectrolytes and as binders in the elaboration of lithium–metal battery prototypes with high charge/discharge efficiency and excellent specific capacity (up to 130 mAh g–1) at C/15 rate.
Single-ion conducting polymer electrolytes represent the ideal solution to reduce concentration polarization in lithium metal batteries (LMBs). This paper reports on the synthesis and ...characterization of single-ion ABA triblock copolymer electrolytes comprising PEO and poly(lithium 1-3-(methacryloyloxy)propylsulfonyl-1-(trifluoromethylsulfonyl)imide) blocks, poly(LiMTFSI). Block copolymers are prepared by reversible addition-fragmentation chain transfer polymerization, showing low glass transition temperature (−55 to 7 °C) and degree of crystallinity (51–0%). Comparatively high values of ionic conductivity are obtained (up to ≈ 10−4 S cm−1 at 70 °C), combined with a lithium-ion transference number close to unity (tLi+ ≈ 0.91) and a 4 V electrochemical stability window. In addition to these promising features, solid polymer electrolytes are successfully tested in lithium metal cells at 70 °C providing long lifetime up to 300 cycles, and stable charge/discharge cycling at C/2 (≈100 mAh g−1).
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•New triblock copolymer electrolytes synthesized by RAFT polymerization.•High ionic conductivity and lithium single ion conduction in polymer electrolytes.•High performance at elevated C-rate in all-solid lithium polymer cells.
Truly solid polymer electrolyte membranes are designed by thermally induced free radical polymerisation. The overall membrane architecture is built on a semi-interpenetrating polymer network (s-IPN) ...structure, where a di-methacrylate oligomer is cross-linked (in situ) in the presence of a long thermoplastic linear PEO chain and a supporting lithium salt to obtain a freestanding, flexible and non-tacky film. In the envisaged systems, the di-methacrylate functions as a soft cross-linker, thus avoiding physico-mechanical deformation of the s-IPNs at elevated temperature, without hampering the ionic conductivity. s-IPNs exhibit remarkable stability towards lithium metal and no traces of impurity are detected while testing their oxidation stability (4.7 V vs. Li/Li+) towards anodic potential. The newly elaborated system is also successfully tested at moderately high temperature in Li metal cells in which LiFePO4/C is used as the cathode active material, showing excellent indications of safe and highly durable electrolyte separator (i.e., 2000 cycles at reasonably high 1C rate).
•Thermally cured semi-interpenetrated solid electrolyte networks.•Simple, cheap thermal polymerisation approach for Li polymer batteries.•Green polymer electrolytes with safe and aging-resistant characteristics.•Stable cycling in Li/LiFePO4 cells at 70 °C for >2000 cycles.
The first example of a photopolymerized electrolyte for a sodium‐ion battery is proposed herein. By means of a preparation process free of solvents, catalysts, purification steps, and separation ...steps, it is possible to obtain a three‐dimensional polymeric network capable of efficient sodium‐ion transport. The thermal properties of the resulting solid electrolyte separator, characterized by means of thermogravimetric and calorimetric techniques, are excellent for use in sustainable energy systems conceived for safe large‐scale grid storage. The photopolymerized electrolyte shows a wide electrochemical stability window up to 4.8 V versus Na/Na+ along with the highest ionic conductivity (5.1 mS cm−1 at 20 °C) obtained in the field of Na‐ion polymer batteries so far and stable long‐term constant‐current charge/discharge cycling. Moreover, the polymeric networks are also demonstrated for the in situ fabrication of electrode/electrolyte composites with excellent interfacial properties, which are ideal for all‐solid‐state, safe, and easily upscalable device assembly.
Shine a light on an electrolyte: The first example of a photopolymer for use as electrolyte in sodium‐ion batteries is proposed. Photopolymerization is an easy and scalable technique useful for the preparation of large‐scale grid storage systems. The resulting polymer exhibits high thermal stability, low glass transition temperature, outstanding ionic conductivity, and wide electrochemical stability window. Assembled lab‐scale quasi‐solid sodium polymer batteries are characterized.
Profoundly ion-conducting, self-standing, and tack-free ethylene oxide-based polymer electrolytes encompassing a room-temperature ionic liquid (RTIL) with specific amounts of lithium salt are ...successfully prepared via a rapid and easily upscalable process including a UV irradiation step. All prepared materials are thoroughly characterized in terms of their physical, chemical, and morphological properties and eventually galvanostatically cycled in lab-scale lithium batteries (LIBs) exploiting a novel direct polymerization procedure to get intimate electrode/electrolyte interfacial characteristics. The promising multipurpose characteristics of the newly elaborated materials are demonstrated by testing them in dye-sensitized solar cells (DSSCs), where the introduction of the iodine/iodide-based redox mediator in the polymer matrix assured the functioning of a lab-scale test cell with conversion efficiency exceeding 6% at 1 sun. The reported results enlighten the promising prospects of the material to be successfully implemented as stable, durable, and efficient electrolyte in next-generation energy conversion and storage devices.
In this work, the possibility of employing aluminium terephthalic acid metal organic framework (Al-TPA-MOF)-laden composite polymer membranes as electrolyte for all-solid-state lithium-sulfur (Li-S) ...and lithium-metal (Li-metal) polymer batteries is explored. The prepared composite polymer electrolytes (CPEs) based on a poly(ethylene oxide) (PEO) network with lithium bis(trifluoromethane)sulfonimide (LiTFSI) and Al-TPA-MOF are mechanically robust and thermally stable up to 270 °C, and provide appreciable ionic conductivity in the order of 0.1 mS cm−1 at 60 °C. The enhanced compatibility of CPEs with the lithium metal anode is attributed to the scavenging effect of Al-TPA-MOF. Laboratory scale all-solid-state Li-S and Li-metal polymer cells are assembled, which deliver specific capacities exceeding 800 and 130 mAh g−1, respectively, and a stable performance upon prolonged cycling even at 60 °C, which is superior to earlier reports on similar systems.
•MOF-laden composite polymer electrolyte (CPE) is proposed for Li-S and Li-metal batteries.•CPE are based on PEO, LiTFSI and Al terephthalic acid MOF (Al-TPA-MOF).•CPE are thermally stable up to >300 °C, with ionic conductivity up to 0.1 mS cm−1 at 60 °C.•Enhanced compatibility with Li metal is attributed to the scavenging effect of Al-TPA-MOF.•Stable cycling in Li-S and Li-metal polymer cells is obtained at 60 °C.
Safety issues rising from the use of conventional liquid electrolytes in lithium-based batteries are currently limiting their application to electric vehicles and large-scale energy storage from ...renewable sources. Polymeric electrolytes represent a solution to this problem due to their intrinsic safety. Ideally, polymer electrolytes should display both high lithium transference number (t Li +) and ionic conductivity. Practically, strategies for increasing t Li + often result in low ionic conductivity and vice versa. Herein, networked polymer electrolytes simultaneously displaying t Li + approaching unity and high ionic conductivity (σ ≈ 10–4 S cm–1 at 25 °C) are presented. Lithium cells operating at room temperature demonstrate the promising prospect of these materials.
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