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Research studies on biomass-derived hard carbon are gaining notable scientific interest due to its potential application as a sustainable anode for Li-ion batteries (LIBs). The current study presents the development of hard carbon from soap-nut seed biomass, with the optimization of its pyrolysis temperature, followed by chemical activation using KOH- and ZnCl2-activated reagents. The physicochemical behaviour of the developed materials is studied by utilizing XRD, HRTEM, BET, and XPS techniques. CV and galvanostatic charge–discharge curves are examined to assess the potential of the material for the application as a sustainable anode in LIBs. The electrochemical performance of the developed materials obtained at various pyrolysis temperatures (600, 700, 800 and 900 °C) and chemically activated with KOH and ZnCl2 is explained with respect to their interplanar spacing, ID/IG ratio, and specific pore area. Among the different pyrolysis temperatures, the hard carbon pyrolyzed at 700 °C exhibits the maximum reversible specific discharge capacity of 391 mA h g−1 at a current density of 100 mA g−1. The present study also demonstrates that the electrochemical performance of the hard carbon deteriorates after chemical activation with ZnCl2, whereas chemical activation with KOH enhances its performance. The chemically-activated hard carbon using KOH exhibits a reversible specific discharge capacity of 454 mA h g−1 at 100 mA g−1 and delivers a better cycling stability (500 cycles) of 83 mA h g−1 at 300 mA g−1. [ABSTRACT FROM AUTHOR]

The escalating need for lithium-ion batteries (LIBs), driven by their expanding range of applications in our daily lives, has led to a surge in interest in metal selenides as potential anode materials. Among them, Bi2Se3 stands out as a promising anode material for LIBs due to its unique layered structure. Herein, we explored hexagonally structured layered Bi2Se3 platelets synthesized using the solvothermal method. The electrochemical performance of these platelets in LIBs was thoroughly examined, revealing an impressive initial discharge specific capacity of 556 mA h g−1 at a current density of 100 mA g−1 and a coulombic efficiency of 66.5%. Improved cycling stability, rate performance, and discharge voltage profile at various current densities were observed. The plateaus observed during the charge/discharge profile were clearly illustrated by the CV results. The reaction kinetics indicated that both ion diffusion and pseudo-capacitance behavior are crucial for the observed high electrochemical performance. Moreover, the hexagonal Bi2Se3 platelets exhibited a high ion-diffusion coefficient of 1.8 × 10−13 cm2 s−1 and a charge transfer impedance of 23 Ω post-cycling. Furthermore, the crystal structure, lattice vibrational bonding, and surface morphology of Bi2Se3 were explored using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. FTIR spectroscopy was utilized for identifying the functional groups, while X-ray photoelectron spectroscopy (XPS) was used to identify the elemental composition and oxidation states of Bi2Se3. [ABSTRACT FROM AUTHOR]

Fluoride-ion batteries (FIBs) offer better theoretical energy densities and temperature stability, making them suitable alternatives to expensive Li-ion batteries. Major studies on FIBs operating at room temperature focus mainly on MSnF4 (M: Ba and Pb) solid electrolytes due to their favourable ionic conductivity values. PbSnF4 is the best fluoride ionic conductor known to date. However, it exhibits poor electrochemical stability. The present work demonstrates the development of TlSn2F5 through a single-step mechanical milling method. TlSn2F5 exhibits a better ionic conductivity value compared to the earlier reported various solid electrolytes, such as BaSnF4, KSn2F5, and La0.9Ba0.1F2.9, commonly considered for FIBs. Ionic transport number measurement using the dc polarization method indicates that TlSn2F5 is an ionic conductor. Furthermore, 19F NMR spectra measured at various temperatures demonstrate that the rise in conductivity with temperature is attributed to the rapid transport of fluoride ions. The present study indicates that TlSn2F5 can be utilized as a potential solid electrolyte for fabricating FIBs. [ABSTRACT FROM AUTHOR]

The escalating need for lithium-ion batteries (LIBs), driven by their expanding range of applications in our daily lives, has led to a surge in interest in metal selenides as potential anode materials. Among them, Bi 2 Se 3 stands out as a promising anode material for LIBs due to its unique layered structure. Herein, we explored hexagonally structured layered Bi 2 Se 3 platelets synthesized using the solvothermal method. The electrochemical performance of these platelets in LIBs was thoroughly examined, revealing an impressive initial discharge specific capacity of 556 mA h g -1 at a current density of 100 mA g -1 and a coulombic efficiency of 66.5%. Improved cycling stability, rate performance, and discharge voltage profile at various current densities were observed. The plateaus observed during the charge/discharge profile were clearly illustrated by the CV results. The reaction kinetics indicated that both ion diffusion and pseudo-capacitance behavior are crucial for the observed high electrochemical performance. Moreover, the hexagonal Bi 2 Se 3 platelets exhibited a high ion-diffusion coefficient of 1.8 × 10 -13 cm 2 s -1 and a charge transfer impedance of 23 Ω post-cycling. Furthermore, the crystal structure, lattice vibrational bonding, and surface morphology of Bi 2 Se 3 were explored using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. FTIR spectroscopy was utilized for identifying the functional groups, while X-ray photoelectron spectroscopy (XPS) was used to identify the elemental composition and oxidation states of Bi 2 Se 3 .

Fluoride-ion batteries (FIBs) offer better theoretical energy densities and temperature stability, making them suitable alternatives to expensive Li-ion batteries. Major studies on FIBs operating at room temperature focus mainly on MSnF 4 (M: Ba and Pb) solid electrolytes due to their favourable ionic conductivity values. PbSnF 4 is the best fluoride ionic conductor known to date. However, it exhibits poor electrochemical stability. The present work demonstrates the development of TlSn 2 F 5 through a single-step mechanical milling method. TlSn 2 F 5 exhibits a better ionic conductivity value compared to the earlier reported various solid electrolytes, such as BaSnF 4 , KSn 2 F 5 , and La 0.9 Ba 0.1 F 2.9 , commonly considered for FIBs. Ionic transport number measurement using the dc polarization method indicates that TlSn 2 F 5 is an ionic conductor. Furthermore, 19 F NMR spectra measured at various temperatures demonstrate that the rise in conductivity with temperature is attributed to the rapid transport of fluoride ions. The present study indicates that TlSn 2 F 5 can be utilized as a potential solid electrolyte for fabricating FIBs.