Organic rechargeable batteries gain huge scientific interest owing to the design flexibility and resource renewability of the active materials. However, the low reduction potentials still remain a challenge to compete with the inorganic cathodes. This study demonstrates a simple and efficient approach to tune the redox properties of perylene diimides (PDIs) as high voltage cathodes for organic‐based sodium‐ion batteries (SIBs). With appropriate electron‐withdrawing groups as substituents on perylene diimides, this study shows a remarkable tunability in the discharge potential from 2.1 to 2.6 V versus Na+/Na with a sodium intake of ≈1.6 ions per molecule. Further, this study explores tuning the shape of the voltage profiles by systematically tuning the dihedral angle in the perylene ring and demonstrates a single plateau discharge profile for tetrabromo‐substituted perylene diimide (dihedral angles θ1 & θ2 = 38°). Detailed structural analysis and electrochemical studies on substituted PDIs unveil the correlation between molecular structure and voltage profile. The results are promising and offer new avenues to tailor the redox properties of organic electrodes, a step closer toward the realization of greener and sustainable electrochemical storage devices.

In article number https://doi.org/10.1002/aenm.201701316, Mahesh Hariharan, Manikoth M. Shaijumon, and co‐workers demonstrate an efficient approach to tune the redox properties of perylene diimides as electrodes for sodium ion batteries by tuning their dihedral angle through appropriate electrophilic substitution. An understanding of structure‐voltage profile correlation is explored to tailor the shape of voltage profile to a single plateau, resulting in enhanced electrochemical properties for such organic electrodes.

Green resources for lithium‐based batteries excite many researchers due to their eco‐friendly nature. In this work, a sustainable bio‐based solid‐state electrolyte was developed based on carbonated soybean oil (CSBO), obtained by organocatalyzed coupling of CO2 to epoxidized soybean oil. CSBO coupled with lithium bis(trifluoromethanesulfonyl)imide salt on a bio‐based cellulose separator resulted in free‐standing membranes. Those membranes on electrochemical measurements exhibited ionic conductivity of around 10−3 S cm−1 at 100 °C and around 10−6 S cm−1 at room temperature with wide electrochemical stability window (up to 4.6 V vs. Li/Li+) and transference number up to 0.39 at RT. Further investigations on the galvanostatic charge‐discharge of LiFePO4 cathodes with CSBO‐based electrolyte membranes and lithium metal anodes delivered the gravimetric capacity of 112 and 157 mAh g−1 at RT and 60 °C, respectively, providing a promising direction to further develop bio‐based solid electrolytes for sustainable solid‐state lithium batteries.

Designing compatible electrode–electrolyte interfaces is critical to achieve high and consistent performance and life span in next-generation rechargeable lithium batteries. In the study of nanoscopic interfaces, ab initio molecular dynamics (AIMD) simulations allow for a highly accurate description of interface dynamics and reactions. However, due to the high computational cost, simulations are limited in the size and time domains and therefore merit the need for a new interpretational approach that can deduce the long-term reactivity from such short yet highly accurate simulations. In this study, this is established by means of bond length distribution analysis through which the reactivity of key solid polymer electrolyte (SPE) polymer functional groups in contact with key electrode materials (graphite, silicon, lithium) and the influence of the electric field and temperature was successfully determined. Bond length distributions were found to respond to environmental changes and relate to the long-term reactivity in which the strength of electrode surface interactions and the accessibility of functional groups were found to be critical factors. Furthermore, the balancing of the SPE polymer mobility and functional group–electrode surface attraction, respectively, kinetic and thermodynamic properties, further suggests a selective spatial orientation of functional groups when exposed to an electric field, which could have great implications for low-temperature and high-current-density environments. The obtained knowledge on how reactive key SPE polymer functional groups are and also how their reactivity changes in terms of the electric field orientation effect could provide new insights for designing new stable SPE polymers.

The solid polymer electrolytes (SPE) based electrochemical devices are an area of attention for more than two decades. The ability of thin-film preparation and leakage proof over the liquid counterpart are the key factors of SPE. In the present work, two different compositions, 80-20 and 85-15, of PVA:KI has been used as a host polymer complex. Where further 10 wt% of p-Si dispersed with PVA:KI complexes. Polymer films have been prepared with standard solution cast techniques, which are further characterized for their electrical conductivity by Electrical Impedance Spectroscopy (EIS). Also, the humidity effect on the ionic conductivity of these thin films is calculated. It is observed that the ionic conductivity of these polymer electrolytes films increases with 58%, 74%, and 89% humidity. To understand the change in this ionic conductivity, the concentration and mobility of ions are also calculated, and it is found that the change in conductivity are predominately influenced due to the mobility of charge carriers.