Exploring Phenolphthalein Polyarylethers as High-Performance Alternative Binders for High-Voltage Cathodes in Lithium-Ion Batteries.

Polyvinylidene fluoride (PVDF) has unique electrochemical oxidation resistance and is the only binder for high-voltage cathode materials in the battery industry for a long time. However, PVDF still has some drawbacks, such as environmental limitations on fluorine, strict requirements for environmental humidity, weak adhesion, and poor lithium ion conductivity. Herein, the long-standing issues associated with high-voltage lithium cobalt oxide (LiCoO2; LCO) are successfully addressed by incorporating phenolphthalein polyetherketone (PEK-C) and phenolphthalein polyethersulfone (PES-C) as binder materials. These binders have unexpected electrochemical oxidation resistance and robustness adhesion, ensure uniform coverage on the surface of LCO, and establish an effective and fast ion-conductive CEI/binder composite layer. By leveraging these favorable characteristics, electrodes based on polyarylether binders demonstrate significantly better cycling and rate performance than their counterparts using traditional PVDF binders. The fast ion-conductive CEI/binder composite layer effectively mitigates adverse reactions at the cathode-electrolyte interface. As anticipated, batteries utilizing phenolphthalein polyarylether binders exhibit capacity retention rates of 88.92% and 80.4% after 200 and 500 cycles at 4.5 and 4.6 V, respectively. The application of binders, such as polyarylether binders, offers a straightforward and inspiring approach for designing high-energy-density battery materials.

A head-to-head comparison of humoral and cellular immune responses of five COVID-19 vaccines in adults in China.

Introduction: Various COVID-19 vaccine trials have shown that vaccines can successfully prevent symptomatic cases of COVID-19 and death. Head-to-head comparisons help to better understand the immune response characteristics of different COVID-19 vaccines in humans. Methods: We randomly selected 20 participants from each of five ongoing Phase II trials of COVID-19 vaccines. Here, SARS-CoV 2-specific immune responses to DNA vaccine (INO-4800), mRNA vaccine (BNT162b2), Adenovirus-vectored vaccine (CONVIDECIA), Protein subunit vaccine (Recombinant COVID- 19 Vaccine (Sf9 Cells)), Inactivated Vaccine (KCONVAC) were examined longitudinally in healthy adults between Jan 15, 2021 and July 5, 2021 for 6 months. RBD-IgG titres were detected by ELISA, neutralising antibody titer were detected by pseudoviral neutralization and immune cell response were detected by flow cytometry. Results: At the first visit (V1), 100% of individuals who received the BNT162b2, CONVIDECIA, or KCONVAC vaccines experienced seroconversion of neutralizing and binding antibodies in the serum. Except for the Recombinant COVID-19 Vaccine (Sf9 Cells) vaccine having the highest neutralizing antibody GMT at the second visit (although there was no statistically significant difference in geometric mean titers between V1 and V2), the rest of the vaccines had the highest levels of binding antibodies and neutralizing antibodies at V1. The neutralizing antibodies GMT of all vaccines showed a significant decrease at V3 compared to V1. The neutralizing antibody GMT against the omicron variant of all vaccines at V1 showed a significant decrease compared to the wild strain. We observed statistically significant differences in Tcm cells and RBD-specific memory B cells among various vaccines. Discussion: BNT162b2 (mRNA vaccine) exhibits the highest antibody levels among the five vaccines evaluated, regardless of whether the target is the wild-type virus or its variants. However, its cellular immune response may be weaker compared to CONVIDECIA (adenovirus type 5 vector vaccine).

Water-Soluble Polyamide Acid Binder with Fast Li+ Transfer Kinetics for Silicon Suboxide Anodes in Lithium-Ion Batteries.

Silicon suboxide (SiOx) anodes have attracted considerable attention owing to their excellent cycling performance and rate capability compared to silicon (Si) anodes. However, SiOx anodes suffer from high volume expansion similar to Si anodes, which has been a challenge in developing suitable commercial binders. In this study, a water-soluble polyamide acid (WS-PAA) binder with ionic bonds was synthesized. The amide bonds inherent in the WS-PAA binder form a stable hydrogen bond with the SiOx anode and provide sufficient mechanical strength for the prepared electrodes. In addition, the ionic bonds introduced by triethylamine (TEA) induce water solubility and new Li+ transport channels to the binder, achieving enhanced electrochemical properties for the resulting SiOx electrodes, such as cycling and rate capability. The SiOx anode with the WS-PAA binder exhibited a high initial capacity of 1004.7 mAh·g-1 at a current density of 0.8 A·g-1 and a capacity retention of 84.9% after 200 cycles. Therefore, WS-PAA is a promising binder for SiOx anodes compared with CMC and SA.

Effects of maternal antibodies in infants on the immunogenicity and safety of inactivated polio vaccine in infants.

The presence of maternal poliovirus antibodies may interfere with the immune response to inactivated polio vaccine (IPV), and its influence on the safety of vaccination is not yet understood. A total of 1146 eligible infants were randomly assigned (1:1) to the IPV and Sabin IPV (SIPV) groups to compare and analyze the efficacy of the two vaccines in preventing poliovirus infection. We pooled the SIPV and IPV groups and reclassified them into the maternal poliovirus antibody-positive group (MAPG; ≥1: 8) and the maternal poliovirus antibody-negative group (MANG; <1: 8). We evaluated the impact of maternal poliovirus antibodies by comparing the geometric mean titer (GMT), seroconversion rate, and geometric mean increase (GMI) of types I-III poliovirus neutralizing antibodies post-vaccination, and incidence rates of adverse reactions following vaccination between the MAPG and MANG. Respective seroconversion rates in the MAPG and MANG were 94% and 100%, 79.27% and 100%, and 93.26% and 100% (all serotypes, P < .01) for types I-III poliovirus, respectively. The GMT of all types of poliovirus antibodies in the MAPG (1319.13, 219.91, 764.11, respectively) were significantly lower than those in the MANG (1584.92, 286.73, 899.59, respectively) (P < .05). The GMI in the MAPG was significantly lower than that in the MANG (P < .05). No statistically significant difference in the incidence of local and systemic adverse reactions was observed between the MAPG and MANG. Thus, the presence of maternal poliovirus antibodies does not affect the safety of IPV but can negatively impact the immune responses in infants after IPV vaccination.

Facile and Powerful In Situ Polymerization Strategy for Sulfur-Based All-Solid Polymer Electrolytes in Lithium Batteries.

All-solid-state polymer electrolytes can improve the safety of lithium batteries. However, the common Bellcore polymer electrolyte technology faces several issues such as wasting a mass of solvent, high manufacturing cost, and poor interfacial compatibility between polymer electrolytes and electrodes. Herein, we propose an in situ polymerization technique to synthesize all-solid-state polymer electrolytes by a thiol-Michael addition click reaction. The alternating copolymer is made from the Michael addition reaction of ethylene glycol dimethacrylate (EGDMA) and 1,2-ethane dithiol (EDT). At ambient temperature, the obtained composite polymer electrolyte displays an ionic conductivity of 3.02 × 10-5 S/cm, an electrochemical window of 4.5 V, and a lithium-ion transference number of 0.45. In light of this unique polymerization process, the traditional fabrication method of liquid electrolyte-based lithium batteries can be adopted in the current study for the preparation of all-solid-state Li/LiFePO4 batteries. It was found that the assembled all-solid-state Li/LiFePO4 batteries exhibited superior charging/discharging performance and preferable safety. Thus, this facile and powerful in situ polymerization strategy may open up a new approach for the design and fabrication of all-solid-state batteries with desirable performances.

Synergy of Single-ion Conductive and Thermo-responsive Copolymer Hydrogels Achieving Anti-Arrhenius Ionic Conductivity.

Artificial intelligence sensations have aroused scientific interest from electronic conductors to bio-inspired ionic conductors. The conductivity of electrons decreases with increasing temperature, while the ionic conductivity agrees with an Arrhenius equation or a modified Vogel-Tammann-Fulcher (VTF) equation. Herein, thermo-responsive poly(N-isopropyl amide) (PNIPAm) and single-ion-conducting poly(2-acrylamido-2-methyl-1-propanesulfonic lithium salt) (PAMPSLi) were copolymerized via a facile radical polymerization to demonstrate a very intriguing anti-Arrhenius ionic conductivity behaviour during thermally induced volume-phase transition. These smart hydrogels presented very promising scaffolds for architecting flexible, wearable or advanced functional ionic devices.

Polyimide film with low thermal expansion and high transparency by self-enhancement of polyimide/SiC nanofibers net.

A facile approach to synthesize a polyimide (PI) film with enhanced dimensional stability, a high mechanical property and optical transparency is presented by embedding the partial imidized PI/SiC nanofiber-net in a poly(amic acid) (PAA) solution, followed by removing the solvent and imidization of the PAA. The nanofiber-network self-filled PI film demonstrates a much lower thermal expansion coefficient (CTE), an excellent mechanical property and high transparency retention in comparison to the film fabricated by solution cast. When the SiC content is 6 wt% in PI/SiC nanofibers, the CTE values for the PI film containing 25 wt% PI/SiC nanofibers are 2.80 times lower than the solution cast PI/SiC film. The tensile strength and modulus for the PI/SiC fiber filled film are also improved by 159% and 91% respectively in comparison to the solution cast SiC/PI film. In addition, the PI/SiC nanofiber-network filled PI film exhibits a high optic transparency. The significant improvement in aforementioned properties is contributed to by the long and continuous nanonetwork which acts as a frame to maintain the stable dimension and endow the film with high mechanical properties. Moreover, the nanosized SiC particles were constricted within the nano-fiber to avoid light scattering, so the high transparency of the film was retained.

Electric-Field-Directed Parallel Alignment Architecting 3D Lithium-Ion Pathways within Solid Composite Electrolyte.

It is of great significance to seek high-performance solid electrolytes via a facile chemistry and simple process for meeting the requirements of solid batteries. Previous reports revealed that ion conducting pathways within ceramic-polymer composite electrolytes mainly occur at ceramic particles and the ceramic-polymer interface. Herein, one facile strategy toward ceramic particles' alignment and assembly induced by an external alternating-current (AC) electric field is presented. It was manifested by an in situ optical microscope that Li1.3Al0.3Ti1.7(PO4)3 particles and poly(ethylene glycol) diacrylate in poly(dimethylsiloxane) (LATP@PEGDA@PDMS) assembled into three-dimensional connected networks on applying an external AC electric field. Scanning electron microscopy revealed that the ceramic LATP particles aligned into a necklacelike assembly. Electrochemical impedance spectroscopy confirmed that the ionic conductivity of this necklacelike alignment was significantly enhanced compared to that of the random one. It was demonstrated that this facile strategy of applying an AC electric field can be a very effective approach for architecting three-dimensional lithium-ion conductive networks within solid composite electrolyte.