Enhancing polysulfide confinement and redox kinetics by electrocatalytic interlayer for highly stable lithium–sulfur batteries

Sodium-Selenium Batteries with Outstanding Rate Capability by Introducing Cubic Mn2 O3 Electrocatalyst

With their high volumetric capacity and electronic conductivity, sodium-selenium (Na-Se) batteries have attracted attention for advanced battery systems. However, the irreversible deposition of sodium selenide (Na2 Se) results in rapid capacity degradation and poor Coulombic efficiency. To address these issues, cubic α-Mn2 O3 is introduced herein as an electrocatalyst to effectively catalyze Na2 Se conversion and improve the utilization of active materials. The results show that the addition of 10 wt% Mn2 O3 in the selenium/Ketjen black (Se/KB) composite enhances the conversion from Na2 Se to Se by lowering activation energy barrier and leads to fast sodium-ion kinetics and low internal resistance. Consequently, the Mn2 O3 -based composite delivers a high specific capacity of 635 mAh ⋅ g-1 at 675 mA ⋅ g-1 after 250 cycles as well as excellent cycling stability for 800 cycles with a high specific capacity of 317 mAh ⋅ g-1 even at the high current density of 3375 mA ⋅ g-1 . Due to the cubic Mn2 O3 electrocatalyst, the performance of the composites is superior to existing state-of-the-art Na-Se batteries reported in the literature.

"Wane and wax" strategy: Enhanced evolution kinetics of liquid phase Li2S4 to Li2S via mutually embedded CNT sponge/Ni-porous carbon electrocatalysts

The lithium-sulfur battery (Li-S) has been considered a promising energy storage system, however, in the practical application of Li-S batteries, considerable challenges remain. One challenge is the low kinetics involved in the conversion of Li2S4 to Li2S. Here, we reveal that highly dispersed Ni nanoparticles play a unique role in the reduction of Li2S4. Ni-porous carbon (Ni-PC) decorated in situ on a free-standing carbon nanotube sponge (CNTS/Ni-PC) enriches the current response of liquid phase Li2S4 and Li2S2 around the cathode more than 8.1 and 5.7 times higher than that of the CNTS blank sample, respectively, greatly boosting the kinetics and decreasing the reaction overpotential of Li2S4 reduction (lower Tafel slope and larger current response). Thus, with the same total overpotential, more space is provided for the concentration difference overpotential, allowing the more soluble polysulfide intermediates farther away from the surface of the conductive materials to be reduced based on the "wane and wax" strategy, and significantly improving the sulfur utilization. Consequently, S@CNTS/Ni-PC delivers excellent rate performance (812.4 mAh·g-1 at 2C) and a remarkable areal capacity of 10.1 mAh·cm-2. This work provides a viable strategy for designing a target catalyst to enhance the conversion kinetics in the Li2S4 reduction process.

Future Trends and Aging Analysis of Battery Energy Storage Systems for Electric Vehicles

The increase of electric vehicles (EVs), environmental concerns, energy preservation, battery selection, and characteristics have demonstrated the headway of EV development. It is known that the battery units require special considerations because of their nature of temperature sensitivity, aging effects, degradation, cost, and sustainability. Hence, EV advancement is currently concerned where batteries are the energy accumulating infers for EVs. This paper discusses recent trends and developments in battery deployment for EVs. Systematic reviews on explicit energy, state-of-charge, thermal efficiency, energy productivity, life cycle, battery size, market revenue, security, and commerciality are provided. The review includes battery-based energy storage advances and their development, characterizations, qualities of power transformation, and evaluation measures with advantages and burdens for EV applications. This study offers a guide for better battery selection based on exceptional performance proposed for traction applications (e.g., BEVs and HEVs), considering EV’s advancement subjected to sustainability issues, such as resource depletion and the release in the environment of ozone and carbon-damaging substances. This study also provides a case study on an aging assessment for the different types of batteries investigated. The case study targeted lithium-ion battery cells and how aging analysis can be influenced by factors such as ambient temperature, cell temperature, and charging and discharging currents. These parameters showed considerable impacts on life cycle numbers, as a capacity fading of 18.42%, between 25–65 °C was observed. Finally, future trends and demand of the lithium-ion batteries market could increase by 11% and 65%, between 2020–2025, for light-duty and heavy-duty EVs.

An in-situ electrodeposited cobalt selenide promotor for polysulfide management targeted stable Lithium-Sulfur batteries

Lithium-sulfur batteries (LSBs) have attracted much attention due to their high theoretical specific capacity, energy density and low cost. However, the commercial application of LSBs is hindered due to the lithium polysulfide (LiPS) shuttle as well as the sluggish reaction kinetics. Herein, cobalt selenide (Co_0.85Se) nanowire arrays have been constructed on a carbon-modified separator by an in-situ electrodeposition technique without any other post-treatments such as coating with other ancillary materials. The introduced three-dimensional (3D) conductive carbon layer comprising of carbon nanotube (CNT) and acetylene black (AB) not only serves as the effective support for Co_0.85Se (CS) but also builds a hierarchical structure to promote the e^- transfer. The as-obtained CS-CNT/AB presents a strong anchoring effect on LiPSs and high electrocatalytic activity for sulfur reaction kinetics. As a result, the LSBs inserted with electrodeposition-enabled CS modified separator exhibit an outstanding rate capability (1560.4 mAh g^-1 at 0.1 C) and relatively low capacity decay of only 0.068% per cycle over 500 cycles at 2.0 C. This study provides a promising strategy to realize the rational construction of high-efficiency and long-life LSBs.