Na-ion batteries represent a promising complementary alternative to Li-ion batteries due to their high energy density and natural abundancy of Na. However, these batteries have short cycle life and extensive research activities on these batteries are required to understand the mechanism of such drawbacks. In this report, we investigate the capacity fading mechanism of NaMnOvia ex situ X-ray diffraction, X-ray absorption spectroscopy, Fourier transform infrared spectroscopy and magnetization measurements. Our results show that the unit cell volume, the effective mass of Mn-O bonds, the number of Mn ions and the effective magnetic moment decrease upon repeated cycling. We propose that some Mn ions in the octahedral environment become Mn ions in a square pyramidal environment, causing oxygen release upon cycling. Any free oxygen in the battery is expected to react with the electrolyte and cause capacity fade.
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http://dx.doi.org/10.1039/c8dt03508c | DOI Listing |
The rapid growth of modern Internet applications demands ever-increasing transmission capacity and reduced latency in optical interconnect systems utilizing intensity modulation and direct detection (IM/DD). However, the intrinsic limitations of silica-based standard single-mode fiber (SMF) will ultimately be insufficient to meet these escalating demands. The nested antiresonant nodeless fiber (NANF), a newly designed hollow-core fiber, has garnered significant attention as a potential solution to these challenges.
View Article and Find Full Text PDFSmall
January 2025
Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei, 230031, P. R. China.
Vanadium-based Na superionic conductor (NASICON) type materials (NaVM(PO), M = transition metals) have attracted extensive attention when used as sodium-ion batteries (SIBs) cathodes due to their stable structures and large Na diffusion channels. However, the materials have poor electrical conductivity and mediocre energy density, which hinder their practical applications. Activating the V/V redox couple (V/V≈4.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Thin film Energy Storage Laboratory, Department of Physics and Nanotechnology, SRM Institute of Science and Technology, Kattankulathur 603 203Tamil Nadu India.
Manganese oxides are a promising cathode material for aqueous zinc-ion batteries (AZIBs), but thin-film configurations remain underexplored. This study investigates the electrochemical dynamics of 60 nm thin MnO thin films, fabricated via RF magnetron reactive sputtering. It addresses the highest reported capacity (25 mAh/g) in thin film form, stability over 500 cycles, effective performance across varying current rates, surpassing previous studies and challenges such as phase stability, and capacity fading over extended cycling, aiming to enhance uniformity, minimizing diffusion barriers for improved performance.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Center for Energy Science and Technology, Skolkovo Institute of Science and Technology, Bolshoy Blvd. 30 build. 1, 121205, Moscow, Russia.
Terminally fluorinated ether 5FDEE shows exceptional compatibility with LiPF, enabling high-performance Li-metal batteries. Li‖NMC811 cells with a 1 M LiPF in 5FDEE : FEC (9 : 1 v/v) electrolyte demonstrate remarkable cycling stability with an average coulombic efficiency exceeding 99.9% and no capacity fading over 550 cycles at 2.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, State Key Laboratory of Crystal Material, Shandong University, Jinan 250100, China.
Architecting Prussian blue analogue (PBA) cathodes with optimized synergistic bimetallic reaction centers is a paradigmatic strategy for devising high-energy sodium-ion batteries (SIBs); however, these cathodes usually suffer from fast capacity fading and sluggish reaction kinetics. To alleviate the above problems, herein, a series of early transition metal (ETM)-late transition metal (LTM)-based PBA (Fe-VO, Fe-TiO, Fe-ZrO, Co-VO, and Fe-Co-VO) cathode materials have been conveniently fabricated via an "acid-assisted synthesis" strategy. As a paradigm, the FeVO-PBA (FV) delivers a superb rate capability (148.
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