ABSTRACT
Rechargeable batteries consisting of a Zn metal anode and a suitable cathode coupled with a Zn2+ ion-conducting electrolyte are recently emerging as promising energy storage devices for stationary applications. However, the formation of high surface area Zn (HSAZ) architectures on the metallic Zn anode deteriorates their performance upon prolonged cycling. In this work, we demonstrate the application of 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA), an organic compound, as a replacement for the Zn-metal anode enabling the design of a 'rocking-chair'zinc-proton hybrid ion battery. The NTCDA electrode material displays a multi-plateau redox behaviour, delivering a specific discharge capacity of 143 mA h g-1 in the potential window of 1.4 V to 0.3 V vs. Zn|Zn2+. The detailed electrochemical characterization of NTCDA in various electrolytes (an aqueous solution of 1 M ZnOTF, an aqueous solution of 0.01 M H2SO4, and an organic electrolyte of 0.5 M ZnOTF/acetonitrile) reveals that the redox processes leading to charge storage involve a contribution from both H+ and Zn2+. The performance of NTCDA as an anode is further demonstrated by pairing it with a MnO2 cathode, and the resulting MnO2||NTCDA full-cell (zinc-proton hybrid ion battery) delivers a specific discharge capacity of 41 mA h gtotal-1 (normalized with the total mass-loading of both anode and cathode active materials) with an average operating voltage of 0.80 V.
ABSTRACT
This work reports the facile synthesis of nonaqueous zinc-ion conducting polymer electrolyte (ZIP) membranes using an ultraviolet (UV)-light-induced photopolymerization technique, with room temperature (RT) ionic conductivity values in the order of 10-3 S cm-1 . The ZIP membranes demonstrate excellent physicochemical and electrochemical properties, including an electrochemical stability window of >2.4 V versus Zn|Zn2+ and dendrite-free plating/stripping processes in symmetric Zn||Zn cells. Besides, a UV-polymerization-assisted in situ process is developed to produce ZIP (abbreviated i-ZIP), which is adopted for the first time to fabricate a nonaqueous zinc-metal polymer battery (ZMPB; VOPO4 |i-ZIP|Zn) and zinc-metal hybrid polymer supercapacitor (ZMPS; activated carbon|i-ZIP|Zn) cells. The VOPO4 cathode employed in ZMPB possesses a layered morphology, exhibiting a high average operating voltage of ≈1.2 V. As compared to the conventional polymer cell assembling approach using the ex situ process, the in situ process is simple and it enhances the overall electrochemical performance, which enables the widespread intrusion of ZMPBs and ZMPSs into the application domain. Indeed, considering the promising aspects of the proposed ZIP and its easy processability, this work opens up a new direction for the emergence of the zinc-based energy storage technologies.
ABSTRACT
Epidermal cysts are very rare. It is more common in males than in females and the most common site of presentation are the hairy sites. We came across two rare cases of epidermal cysts. In one case, a parous lady presented with an adnexal mass and D/D of broad ligament fibroid or ovarian mass was considered which turned out to be a cyst containing cheesy pultaceous material. In the other case, a parous lady presented with a mass arising from the posterior fourchette that contained cheesy pultaceous material on excision. In both cases histopathology confirmed it to be epidermal cysts. Epidermal cysts known for its rare incidence by itself is now found to be presenting at rare sites which emphasizes on the need for further research into the etiopathogenesis of these cysts and its development at the various sites of the body.
