Open Access
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23 September 2025Side Chain Piperidinium Functionalized AEMs with an Ethylene Oxide Spacer for Improving Ion Conductivity and Alkaline Stability
In this work, grafting alkaline stable piperidinium cations via ethylene oxide (EO) spacers onto an aryl ether-free poly(oxindole terphenylene) backbone was adopted as a strategy for designing self-aggregating side chain AEMs with optimized alkaline stability. Aryl ether-free poly(oxindole terphenylene) backbones were synthesized via superacid-catalyzed step-growth polycondensation and were subsequently functionalized with either piperidinium containing hydrophilic, dipolar EO or hydrophobic alkyl spacer, aiming to explore the effect of side chain-engineering on conductivity and alkaline stability of the resulting AEMs. The AEM membrane containing dipolar ethylene oxide spacer, despite its lower ion exchange capacity (IEC), exhibited a more pronounced microphase separated morphology as evidenced by TEM, and higher ionic conductivity (reaching up to 30.5 mS cm−1 at 80 °C) compared to the hydrophobic alkyl spacer-containing AEM membrane. This was attributed to its higher water uptake stemming from the EO hydrophilic nature and the formation of interconnected ion-conducting channels due to piperidinium–EO interactions. Additionally, the hydrophilic nature of the ethylene oxide groups endowed the membrane with enhanced alkaline stability, preserving its mechanical integrity and retaining 71.5% of its initial conductivity after 3 weeks of immersion in 2 M KOH at 80 °C. In contrast, the AEM with an alkyl spacer experienced severe degradation under the same conditions. These results suggest that incorporating flexible alkoxy-containing spacers onto an aryl ether-free backbone is a promising and simple route for fabricating mechanically and chemically robust AEMs with sufficient conductivity.
Open Access
Article
29 October 2025Material Analysis of CNT’s as Conductive Additive for NMC Lithium-Ion Polymer Batteries Cathode Electrode
Carbon nanotubes (CNTs) are promising conductive additives for lithium-ion polymer (LiPo) batteries. The performance of lithium metal oxide cathodes is highly dependent on the properties of the conductive carbon additive. This study investigates the advantages of CNTs over conventional carbon black for this application. Material properties, including hardness, tensile strength, thermal conductivity, and electrical resistivity, were analyzed and compared using Ansys Granta (CES EduPack 2024 R2) software. The results demonstrate that CNTs are superior in tensile strength (110 MPa), hardness (50 HV), and thermal conductivity (210 W/m·°C). These properties enhance the mechanical integrity of the CNT-based cathode composite, leading to improved battery performance. Furthermore, the electrochemical behavior of CNT/LiNi0.5Co0.2Mn0.3O2 composite cathodes was investigated, focusing on the carbon precursor (methane vs. natural gas) and CNT diameter. At a current rate of 3 °C, multi-walled carbon nanotubes (MWCNTs) derived from methane delivered a specific capacity 20 mAh/g higher than those derived from natural gas. This indicates that methane-derived MWCNTs exhibit superior electrochemical performance, which is attributed to reduced polarization and a higher discharge potential. The study also revealed that MWCNTs with a smaller diameter (30–50 nm) performed better at high charge/discharge rates, owing to a higher number of primary particles per unit mass. This analysis aids in understanding material selection and its implications for battery design and lifecycle. The findings serve as a reference for future research exploring the use of CNTs in advanced battery materials.
