Mass Transport in “Water-in-Polymer Salt” Electrolytes

“Water-in-polymer salt” electrolytes (WiPSEs) based on potassium polyacrylate (PAAK) belong to a new family of “water-in-salt” electrolytes that is envisioned as a potential solution for large-scale supercapacitors to balance the electric grid at short time scales. The WiPSEs display a broad electrochemical stability window up to 3 V, yet they are nonflammable and provide high ionic conductivity (100 mS/cm) as required in high-power devices. However, the transport of matter in PAAK-based WiPSEs has not been studied. In this work, we have extensively characterized PAAK by spectroscopic methods such as Raman spectroscopy and NMR diffusometry to determine the state of water and elucidate the mechanism of ionic transport as well as its interplay with water and polymer chain dynamics, which reveals that a significant proportion of the transport in WiPSEs is attributed to hydrated cations. The results are further supported by molecular dynamics (MD) simulations. Finally, the potential of WiPSEs based on PAAK is demonstrated in an activated carbon-based supercapacitor operating up to 2 V with reasonable self-discharge. This proof of concept shows promise for low-cost and large-scale supercapacitors

HIERARCHICAL MATERIAL INCLUDING URCHIN SHAPED MnO2, METHODE FOR SYNTHESIS THE SAME, AND AIR ELECTRODE AND METAL-AIR BATTERY INCLUDING THE SAME

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Highly Porous Graphitic Carbon using the waste paper, METHOD FOR THE SAME, NEGATIVE ELECTRODE INCLUDING THE SAME AND ENERGY STORAGE SYSTEM INCLUDING THE SAME

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Does Water-in-Salt Electrolyte Subdue Issues of Zn Batteries?

Zn-metal batteries (ZnBs) are safe and sustainable because of their operability in aqueous electrolytes, abundance of Zn, and recyclability. However, the thermodynamic instability of Zn metal in aqueous electrolytes is a major bottleneck for its commercialization. As such, Zn deposition (Zn2+ &amp; RARR; Zn(s)) is continuously accompanied by the hydrogen evolution reaction (HER) (2H(+) &amp; RARR; H-2) and dendritic growth that further accentuate the HER. Consequently, the local pH around the Zn electrode increases and promotes the formation of inactive and/or poorly conductive Zn passivation species (Zn + 2H(2)O &amp; RARR; Zn(OH)(2) + H-2) on the Zn. This aggravates the consumption of Zn and electrolyte and degrades the performance of ZnB. To propel HER beyond its thermodynamic potential (0 V vs standard hydrogen electrode (SHE) at pH 0), the concept of water-in-salt-electrolyte (WISE) has been employed in ZnBs. Since the publication of the first article on WISE for ZnB in 2016, this research area has progressed continuously. Here, an overview and discussion on this promising research direction for accelerating the maturity of ZnBs is provided. The review briefly describes the current issues with conventional aqueous electrolyte in ZnBs, including a historic overview and basic understanding of WISE. Furthermore, the application scenarios of WISE in ZnBs are detailed, with the description of various key mechanisms (e.g., side reactions, Zn electrodeposition, anions or cations intercalation in metal oxide or graphite, and ion transport at low temperature).Funding Agencies|Knut and Alice Wallenberg (KAW) foundation [KAW 2020.0174]; Wallenberg Initiative Materials Science for Sustainability WISE; Swedish Energy Agency (SESBC competence center) [P52023-1, 526701]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoeping University (Faculty Grant SFO-Mat-LiU ) [2009-00971]; Aforsk foundation [21-130, 22134]</p

Can Hybrid Na-Air Batteries Outperform Nonaqueous Na-O-2 Batteries?

In recent years, there has been an upsurge in the study of novel and alternative energy storage devices beyond lithium-based systems due to the exponential increase in price of lithium. Sodium (Na) metal-based batteries can be a possible alternative to lithium-based batteries due to the similar electrochemical voltage of Na and Li together with the thousand times higher natural abundance of Na compared to Li. Though two different kinds of Na-O-2 batteries have been studied specifically based on electrolytes until now, very recently, a hybrid Na-air cell has shown distinctive advantage over nonaqueous cell systems. Hybrid Na-air batteries provide a fundamental advantage due to the formation of highly soluble discharge product (sodium hydroxide) which leads to low overpotentials for charge and discharge processes, high electrical energy efficiency, and good cyclic stability. Herein, the current status and challenges associated with hybrid Na-air batteries are reported. Also, a brief description of nonaqueous Na-O-2 batteries and its close competition with hybrid Na-air batteries are provided.Funding Agencies|Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]</p

Sustainable stretchable batteries for next-generation wearables

Next-generation wearables will interface intimately with the human body either on-skin, implanted or woven into clothing. This requires electrical components that match the mechanical properties of biological tissues - stretchability (up to 60% strain) and softness (Youngs modulus of similar to 1 kPa to 1 MPa). As wearables become increasingly complex, the energy and mechanical requirements will increase, and an integrated power supply unit such as a soft and stretchable battery is needed to achieve autonomy and wireless operation. However, two key challenges remain for current stretchable battery technology: the mechanical performance (softness and stretchability) and its relation to the size and charge storage capacity (challenge I), and the sustainability and biocompatibility of the battery materials and its components (challenge II). Integrating all these factors into the battery design often leads to a trade-off between the various properties. This perspective will evaluate current strategies for achieving sustainable stretchable batteries and provide a discussion on possible avenues for future research. Stretchable battery technology still faces several challenges to progress the development of next-generation wearables. This perspective will evaluate current strategies and provide a discussion on possible avenues for future research.Funding Agencies|Swedish Governmental Agency for Innovation Systems, VINNOVA [2021-01668]; Knut and Alice Wallenberg Foundation; Linkoeping University; Wallenberg Wood Science Centre; Swedish Research Council [2020-05218]; Wallenberg Initiative Materials Science for Sustainability (WISE) - Knut and Alice Wallenberg Foundation</p

Bagasse derived C@Fe3C/Fe3O4 composite: An Approach towards low cost electrocatalyst for oxygen reduction reaction

As the world is heading towards sustainable future, it is highly important to develop low-cost electrocatalysts for energy generation devices. Herein, we report synthesis of iron-carbon hybrid (C@Fe3C/Fe3O4) nanocomposite for oxygen reduction reaction (ORR), synthesized using bagasse as a carbon source material and Fe(III) precursor at 900 ˚C. The synthesized C@Fe3C/Fe3O4 composite exhibits a high surface area of ~930 m2/g. The electrode material has a 0.86 V overpotential vs RHE. Moreover, the electrocatalyst shows catalytic stability upto 44,000 s at the static potential of 0.25 V vs RHE at the rotation speed of 1600 rpm. Herein, the electron transfer number is calculated to be 3.76-3.94 which suggest that the electrocatalyst could catalyze ORR nearly through a 4 electron transfer process in alkaline solution

Rechargeable Na/Ni batteries based on the Ni(OH)2/NiOOH redox couple with high energy density and good cycling performance

Rechargeable battery systems that use Na-based anodes as alternatives to Li-ion batteries are highly desirable for grid-scale energy storage systems owing to the high abundance and low cost of Na. Furthermore, aqueous Na batteries are advantageous considering the cost, safety and cycle life. However, the limited energy density is still a critical issue for Na-based batteries. Here, we demonstrate a high performance rechargeable battery using dual electrolytes based on a Na metal anode and a redox couple of hierarchical NiCoAl-layered double hydroxide (NiCoAl-LDH) nanosheets on a carbon microfiber electrode with high energy storage capacity. In this design, the wide potential range of the Na metal anode and the high capacity of hierarchical NiCoAl-LDH nanosheets on a carbon microfiber cathode enable a rechargeable Na/Ni battery with excellent energy storage performance. For stable operation in a hybrid system using non-aqueous and aqueous electrolytes, an alkali-ion solid electrolyte (NASICON, Na3Zr2Si2PO12) is used for the separation of electrolytes. The Na/Ni battery exhibits a stable operating voltage of ???3.1 V during discharge which outperforms the low cell voltage (???1.23 V) of an aqueous rechargeable battery, a high capacity of ???350 mA h g-1, and a resulting high energy density of ???1085 W h kg-1. With the combination of a solid-state redox couple as the cathode and a metallic sodium anode, our study demonstrates the high potential of Na based batteries for high energy EES systems

Earth-abundant stable elemental semiconductor red phosphorus-based hybrids for environmental remediation and energy storage applications

The photocatalytic generation of hydrogen and the photodegradation of organic dyes in wastewater using solar light, preferably visible light, have attracted considerable interest because they are clean, low-cost, and environmentally friendly processes. On the other hand, the major drawbacks with traditional photocatalysts are their limited light absorption ability and wide band gap. Therefore, several studies have focused on elemental semiconductor photocatalysts such as red phosphorus (RP) because of its narrow band gap, high absorption ability for the incident solar spectrum, low cost, earth abundance, and easy accessibility, showing great potential for use in numerous industrial applications. The development of RP and its heterojunctions provides promising candidates for utilizing the largest part of the solar energy spectrum. In addition to the photoinduced properties of RP-based nanocomposites, RP-based nanocomposite materials have recently been considered to be good and advanced anodes for lithium-and sodium-ion batteries because of the high theoretical capacity of RP (2596 mA h g(-1)). The present review briefly introduces the recent advances in the development of various strategies for constructing efficient RP-based hybrid structures that are responsive to visible light, followed by a description of the utilization of RP and its composites as electrode materials in lithium-and sodium-ion batteries. Finally, a summary and viewpoint are also presented to highlight future work on the development of high-storage RP-based electrodes and visible-light photocatalystsclos