An enhanced polaron conductivity in LiFePO4 by decreasing the crystallite size as evidenced due to the reduction of hopping length of electrons and enhanced polaron concentrations.

Alkaline‐earth based coordination polymers (CPs) with rigid frameworks are promising candidates for future dielectrics. During our attempts to engineer new calcium and strontium dicarboxylates under solvothermal condition, we synthesized six CPs, namely, [Sr(BDC)(DMA)(H2O)] (1), [Ca(ABDC)(DMF)] (2), [Ca(ABDC)(DMA)2/3] (3), [Sr(ABDC)(DMF)] (4), [Sr(OBA)(MF)] (5) and {[Sr(FBA)(DMA)(H2O)].(DMA)(EtOH)(H2O)]} (6) [where, BDC=1,4‐benzenedicarboxylic acid, ABDC=2‐aminoterephthalic acid, OBA=4,4’‐oxybis(benzoic acid) and FBA=4,4’‐(hexafluoroisopropylidene)bis(benzoic acid)] and established its full structures using single crystal X‐ray crystallography. A significant structural feature of all the solids was the occurrence of rigid 1D columns made of metal carboxylate coordination. All the solids showed interesting dielectric behaviour and exhibited photoluminescence with blue or bluish‐green emission.

Six coordination polymers based on Mn(ii) and V-shaped ligand were successfully isolated and their dielectric as well as magnetic behaviours were investigated. The paper also discusses the growth of solids in terms of supramolecular aggregation.

The structural properties of heterosite FePO4 were found to exhibit crystallite size dependence below 50 nm; the change in the structural behavior with crystallite size is correlated with the change in the chemical bonding.

The optimization of a cathode material is the most important criterion of lithium ion battery technology, which decides the power density. In order to improve the rate capability, a cathode material must possess high electronic and ionic conductivities. Therefore, it is important to understand the charge transport mechanism in such an advanced cathode material in its intrinsic state before modifying it by various means. In this work, we report the thermal, structural, and electrical conductivity studies on lithium iron phosphate, LiFePO4, both in its polycrystalline (LFPC) and glassy (LFPG) counterpart states. The vibrational spectroscopic measurements reveal the characteristic vibrational modes, which are the intrinsic part of LFPC, whereas in LFPG, the phonon modes become broader and overlap with each other due to the lattice disorder. The electrical conductivity measurements reveal that LFPG exhibits a higher polaronic conductivity of 1.6 orders than the LFPC sample. The temperature dependent dc conductivity has been analyzed with the Mott model of polarons and reveals the origin of enhanced polaronic conductivity in LFPG. Based on the analysis, the enhanced polaronic conductivity in LFPG has been attributed to the combined effect of reduced hopping length, decreased activation energy, and enhanced polaron concentration.