Mechanical Stabilization of Solid Polymer Electrolytes through Gamma Irradiation

Improving the Electrochemical Stability of a Polyester-Polycarbonate Solid Polymer Electrolyte by Zwitterionic Additives

Rechargeable batteries with solid polymer electrolytes (SPEs), Li-metal anodes, and high-voltage cathodes like LiNi _x Mn _y Co _z O₂ (NMC) are promising next-generation high-energy-density storage solutions. However, these types of cells typically experience rapid failure during galvanostatic cycling, visible as an incoherent voltage noise during charging. Herein, two imidazolium-based zwitterions, with varied sulfonate-bearing chain length, are added to a poly(ε-caprolactone-co-trimethylene carbonate):LiTFSI electrolyte as cycling-enhancing additives to study their effect on the electrochemical stability of the electrolyte and the cycling performance of half-cells with NMC cathodes. The oxidative stability is studied with two different voltammetric methods using cells with inert working electrodes: the commonly used cyclic voltammetry and staircase voltammetry. The specific effects of the NMC cathode on the electrolyte stability is moreover investigated with cutoff increase cell cycling (CICC) to study the chemical and electrochemical compatibility between the active material and the SPE. Zwitterionic additives proved to enhance the electrochemical stability of the SPE and to facilitate improved galvanostatic cycling stability in half-cells with NMC by preventing the decomposition of LiTFSI at the polymer-cathode interface, as indicated by X-ray photoelectron spectroscopy (XPS).

New insights on the origin of chemical instabilities between poly(carbonate)-based polymer and Li-containing inorganic materials

Composites electrolytes, owing to their potential to combine both polymeric and ceramic properties, are promising candidates for Solid-State-Batteries (SSBs). Here, we assessed the effect of ceramic fillers (Li1+xAlxTi2-xP3O12, Li6.55Ga0.15La3Zr2O12, Al2O3) in a poly(ethylene oxide carbonate)-LiTFSI. First, the role of filler chemistry on thermal and electrochemical properties is evaluated: the polymer crystallinity is reduced, resulting in a gain of ionic conductivity at low temperatures; and the ionic conductivity at low temperature (<30 °C) is boosted for LLZO filler particles. This behaviour is commonly attributed to new conduction pathways generated within the fillers; however, here we demonstrate that a polymer degradation induced by the filler chemistry modifies the polymer chemistry in poly(ethylene glycol), initiated by LiOH that can be found on the LLZO surface. The electrolyte containing LATP or Al2O3 does not under any degradation. Hence, special attention must be paid to surface impurities, as instability/degradation may occur.

Synthesis of composite membranes from polyacrylonitrile/carbon resorcinol/formaldehyde xerogels: gamma effect study, characterization and ultrafiltration of salted oily wastewater

The subsequent activated carbons of resorcinol-formaldehyde xerogels are synthesized and exposed to wide range of gamma irradiation dose. Xerogels and their subsequent activated carbons are characterized by diverse techniques; FTIR, Raman, porosity analysis, SEM, EDX and AFM. The composite membranes are fabricated from polyacrylonitrile and activated carbon xerogels as composite membranes to be utilized in ultrafiltration process of salted oily wastewater. The soybean oil is exploited as organic feeding solution. The results declared that values of flux and rejection reach 157 (L m−2 h−1) and 99.8 (%), respectively. Overall, the best performing composite membrane is conducted by maximizing pure water flux. The optimally synthesized membrane performs well for purification of salted oily wastewater, and a significant increment in permeate flux is obtained with soybean oil rejection is at ∼99.8% and with maximum flux is at 32 (L m−2 h−1). Further, the composite membranes showed good promise for ultrafiltration of salted oily wastewater.

UV-Cured Cross-Linked Astounding Conductive Polymer Electrolyte for Safe and High-Performance Li-Ion Batteries

UV-cured cross-linked polymer electrolytes are promising electrolytes for safe Li-ion batteries (LIBs) application due to their excellent conduction ability, low glass-transition temperature (T_g), and high discharge capacity. Herein, we have prepared novel fluorosulfonylimide methacrylic-based cross-linked polymer electrolyte membranes for LIBs via UV-curing process, which is a well-known, easy, low-cost, fast, and reliable technique. The synthesized UV-reactive novel methacrylate monomer with directly attached fluorosulfonylimide functional group methacryloylcarbamoyl sulfamoyl fluoride (MACSF) was used as a precursor for UV curing along with poly(ethylene glycol) dimethacrylate (PEGDMA) and lithium bis(fluorosulfonyl)imide (LiFSI). The results demonstrated that the cross-linked membrane with an optimized amount (30 wt %) of MACSF monomer (noted as CPE-3) showed the best performance. The nonflammable fluorosulfonyl group (a hydrophilic group of MACSF monomer) in the polymer matrix formed a wide channel, as a result of which Li ion can migrate easily via forming an ionic linkage. The CPE-3 electrolyte exhibited a low T_g (-79 °C), excellent phase separation, high conductivity (σ) (ca. 3.5 × 10^-4 and 8.50 × 10^-3 S·cm^-1 at 30 and 80 °C, respectively), and high flame retardancy. The battery performance of half-cell (LiFePO₄/CPE-3/Li) and full cell (LiFePO₄/CPE-3/graphite) with CPE-3 electrolyte were attractive: discharge capacities (155 and 152 mAh/g) with the capacity retentions of 96.17 and 95.17% after 500 cycles at 0.1 C rate for half-cell and full-cell LIBs, respectively.

Macromolecular Design of Lithium Conductive Polymer as Electrolyte for Solid-State Lithium Batteries

In the development of solid-state lithium batteries, solid polymer electrolyte (SPE) has drawn extensive concerns for its thermal and chemical stability, low density, and good processability. Especially SPE efficiently suppresses the formation of lithium dendrite and promotes battery safety. However, most of SPE is derived from the matrix with simple functional group, which suffers from low ionic conductivity, reduced mechanical properties after conductivity modification, bad electrochemical stability, and low lithium-ion transference number. Appling macromolecular design with multiple functional groups to polymer matrix is accepted as a strategy to solve the problems of SPE fundamentally. In this review, macromolecular design based on lithium conducting groups is summarized including copolymerization, network construction, and grafting. Meanwhile, the construction of single-ion conductor polymer is also focused herein. Moreover, synergistic effects between the designed matrix, lithium salt, and fillers are reviewed with the objective to further improve the performance of SPE. At last, future studies on macromolecular design are proposed in the development of SPE for solid-state batteries with high energy density and durability.

ε-Caprolactone-based solid polymer electrolytes for lithium-ion batteries: synthesis, electrochemical characterization and mechanical stabilization by block copolymerization

Three different polymers were synthesized and evaluated as solid polymer electrolytes: poly(ε-caprolactone) (PCL), polystyrene-poly(ε-caprolactone) (SC), and polystyrene-poly(ε-caprolactone-r-trimethylene carbonate) (SCT).