Current Smart Materials - Volume 5, Issue 1, 2021

Reliable energy storage is a censorious need for an extensive range of requisite such as portable electronic devices, transportation, medical devices, spacecraft and elsewhere. Among the known storage devices, the lithium ion (Li⁺) batteries have enticed attention because of higher theoretical energy density. Nevertheless, the state-of-the-art electrolyte in lithium batteries utilizing a Li⁺ salt dissolved in organic-type solvents poses severe safety concerns like flammability arising from dendrite formation. Next generation (beyond Li⁺) battery systems such as lithium sulphur (Li-S) batteries have gained interest in recent times. This battery system has been extensively revisited in an attempt to develop high energy batteries and is now considered as the technology of choice for hybrid vehicle electrification and grid storage. Higher theoretical capacity and higher theoretical energy density, environmental friendliness and low cost of active material make the Li-S batteries an ideal candidate to meet increasing energy requirements. This review looks at various advanced electrolytic systems with much emphasis on solid state electrolytic systems for Li-S batteries because of their striking properties. The technical issues of the sulphur cathode are also summarized and the strategies followed in recent years are highlighted in this review to address these issues. It is anticipated that Li-S batteries with efficient solid electrolytic system may replace the conventional insertion-type low energy density Li⁺ batteries in the near future.

In the last few decades, as an understanding of polymers grew, their applications in healthcare gained prominence. However, their widespread use was limited due to inevitable ageing, unavoidable degradation and excessive wear and tear. In order to overcome this drawback, researchers took inspiration from the capability of the human body to heal itself. Scientific curiosity and focussed efforts in this direction have laid the foundation for the successful conceptualization of selfhealing polymeric biomaterials and their commercial utilization for ancillary purposes. This review familiarizes the readers with recent literature in self-healing polymers, their fabrication techniques as well as applications in medical and pharmaceutical arenas. It is heartening to note that these polymeric materials have overcome the disadvantages of conventional polymers and shown immense promise in breakthrough technologies such as tissue engineering, anti-biofouling as well as 3D and 4D printing. Self-healing polymers are poised to become critical supporting biomaterials in traditional disciplines such as orthopaedics, dentistry and pharmaceutical drug delivery. Efforts are on to design novel self-healing materials that meet the regulatory requirements of safety and biocompatibility. Research trends indicate that self-healing polymers may play a pivotal supporting role in furthering advances in therapeutics. The authors have, through this review, attempted to spark interest and stimulate creative minds to work in this domain.

Aims: To develop a simple and cost effective synthetic strategy for the preparation of Fe substituted ZnO nanoparticles. Background: The optoelectronic, electrical, dielectric, optical and magnetic properties of nanocrystalline transition metal substituted ZnO are being explored worldwide for a variety of applications in optoelectronic devices, solar cells, transparent thin film transistors, ultraviolet photodetector, piezoelectric devices, light emitting diodes as well as in the biomedical field. Fe substituted ZnO nanoparticles are being looked upon as promising material in dilute magnetic semiconductor system. Objective: To establish chemical identity and purity in order to ensure the complete substitution of Fe³⁺ in ZnO lattice and study the effect of Fe substitution on dielectric, electrical and photocatalytic behavior of ZnO nanoparticles. Methods: The nearly spherical ZnO and Fe substituted ZnO nanoparticles were synthesized at a low temperature via solution combustion synthesis employing metal nitrate and sucrose. Result: The powder X-ray diffraction measurement has revealed the monophasic character and complete substitution of Fe in the wurtzitic ZnO lattice. The lattice constants and aspect ratio of Fe substituted ZnO were nearly constant and comparable to that of pristine ZnO. The average crystallite size was found to decrease with increasing Fe substitution. SEM images revealed porous spongy network like morphology. TEM measurements revealed a nearly spherical particle with narrow size distribution between 10 nm - 25 nm. Conclusion: The dielectric constant and dielectric loss decrease upto x = 0.04 and increases with further increase in Fe concentration. The lower value of dielectric loss in the higher frequency region indicates the less lossy nature of Fe substituted samples. AC conductivity behaviour suggests small polaron hopping type of conduction mechanism. The RT DC resistivity was found to decrease with increasing Fe substitution. Pristine ZnO displayed very high degradation efficiency for photodegradation of MB dye. The photodegradation efficiency was found to decrease considerably with increasing Fe substitution.