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Recently, lithium-sulfur batteries have captivated those in the energy storage industry due to the low cost and high theoretical capacity of the sulfur cathode (1675 mA h g -1 ). However, to enhance the practical usability of Li-S batteries, it is crucial to address issues such as the insulating nature of sulfur cathodes and the high solubility of lithium polysulfides (LiPS, Li 2 S x , 4 ≤ n ≤ 8) that cause poor active sulfur utilization. Designing innovative sulfur hosts can effectively overcome sulfur bottlenecks and achieve stable Li-sulfur batteries. This study presents novel hollow porous structures of Ni-doped MnO 2 encapsulated with multi-walled carbon nanotubes (CNTs) used as an efficient host material for a sulfur cathode. These hollow, porous, hierarchical structures, combined with transition metal (Ni) doping, serve to enhance the adsorption of LiPS and contribute to improved redox kinetics during the electrochemical process. Furthermore, the remarkable conductivity provided by the CNT encapsulation significantly enhances the sulfur and LiPS conversion kinetics, effectively suppressing the undesirable shuttling effect and promoting efficient utilization of the active material. The prepared cathode (S@Ni-MO/CNT) not only meets but exceeds expectations, delivering superior cyclability, rate capability results, and improved Li-diffusion properties. These results underscore the effectiveness of constructing novel host materials for sulfur cathodes, leaving no doubt about the potential of this novel host material to address the challenges in lithium-sulfur batteries., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (This journal is © The Royal Society of Chemistry.)

Herein, we report for the first time a simple strategy to design a hierarchical chemically exfoliated magnesium diboride and guar gum network structure decorated with Ru nanoparticles (eMgB 2 -GG@Ru) as an electrode to evaluate its electrochemical performance for the application of supercapacitor. The eMgB 2 and functionalized eMgB 2 -GG@Ru materials were thoroughly examined using XRD, TGA, DLS, FE-SEM, STEM, AFM, XPS, and BET techniques. The combined eMgB 2 -GG@Ru electrode exhibits a network structure morphology with an increased interlayer distance of eMgB 2 nanolayers along with a uniform distribution of spherical Ru nanoparticles. The electrochemical performance of eMgB 2 -GG@Ru and its pristine materials was studied through CV, GCD, and EIS to determine their supercapacitor performance. The eMgB 2 -GG@Ru electrode demonstrates higher specific capacitance (352 F/g) than its eMgB 2 @Ru (258.9 F/g), and MgB 2 (214.5 F/g) counterparts at a current density of 0.5 A/g in a three-electrode setup using 3 M KOH electrolyte. The hierarchical eMgB 2 -GG@Ru solid-state symmetric devices maintained higher capacity retention of 89 % even after 7000 cycles, achieving a maximum energy density of 26.12 kW/kg at the power density of 450 W/kg at 0.5 A/g. Therefore, the innovative eMgB 2 -GG@Ru electrode offers superior electrochemical performance with efficient electrolyte ion mobility for energy storage applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Metal oxides with hollow porous structures are attractive and promising anode candidates for Li-ion batteries due to their high surface area, high loading capacity, and low density. In this work, hierarchical hollow porous structures of nickel (Ni)-doped λ-MnO 2 were prepared via a facile, and cost-effective approach, where different amounts of Ni were introduced into MnO 2 structures to tailor their physical and chemical properties. When the prepared Ni-doped MnO 2 hollow structures were studied as anode materials for Li-ion batteries, the electrode showed excellent electrochemical properties, such as stable cyclability and admirable rate capability. Moreover, Ni doping significantly enhances the diffusion properties of the active materials. The material was also investigated as an anode in another high power and energy Li-ion storage device, namely, a Li-ion hybrid capacitor, which exhibited excellent comprehensive electrochemical performance in terms of good specific cell capacity of 25 mA h g -1 at a high current density of 5 A g -1 and achieved a maximum power density of 29 W kg -1 (with energy density of 30 W h kg -1 ) with a long cycle life. These results indicate that the Ni-doped MnO 2 is suitable for application as an anode material and give considerable insight into future Li-energy storage applications., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

Lithium-sulfur (Li-S) batteries are considered promising next-generation energy storage devices due to their low cost and high energy density (2600 W h kg -1 ). However, the practical applicability of Li-S batteries is hindered by the insulating nature of sulfur cathodes, and the high solubility of polysulfides (Li 2 S x , 3 < x ≤ 8) which are formed during the electrochemical process. Integrating sulfur into the carbon host is an effective way to enhance the conductivity of the electrode which hampers the shuttling effect of the polysulfides. Here in this study, hierarchical porous carbon structures (HPC) are prepared from spent coffee waste (SCW) by the KOH activation process and are encapsulated with sulfur (SHPC) which increases the interaction between sulfur and carbon and enhances both the electronic and ionic conductivities. Further wrapping of SHPC with N-doped multi-walled carbon nanotubes (NCNTs) gives a SHPC-NCNT composite, which alleviates the shuttling of polysulfides by trapping them and ensures the required conductivity to the sulfur cathode during the Li + reactions. When studied as a cathode material for Li-S batteries, the prepared cathode showed 664 and 532 mA h g -1 specific capacities after 150 cycles at 0.2C and 0.5C, respectively. The stable cyclability and rate capability properties of SPHCNCNT suggest that the prepared sulfur composite is suitable as a cathode material for Li + energy storage applications., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (This journal is © The Royal Society of Chemistry.)

This work has developed a straightforward approach to obtaining NiO hollow structures by using Li 2 O 2 as an easily removable template. The easy availability and electrochemically active nature of NiO have attracted researchers' attention as an anode electrode for Li-ion storage applications, including Li-ion secondary batteries (LIBs) and for Li-ion hybrid supercapacitors (LiHSCs; which offer higher power densities than LIBs without compromising energy density). However, NiO usage has been limited to its low reaction reversibility, poor conductivity, and conversion reaction capability. Recently, hollow nanostructured materials have attracted attention as efficient battery materials due to their fascinating structural features. This study presents a modified Li 2 O 2 -assisted method to obtain porous open 3D architectures of NiO nanostructures. The resultant hollow structures are electrochemically studied as an anode for a LIB, exhibiting excellent stability over hundreds of cycles. The result is recognized as one of the finest among NiO anodes reported. Also, NiO hollow structures studied as anodes for LiHSC devices fabricated with activated carbon cathodes exhibit an outstanding comprehensive electrochemical performance which is better than the typical LIB and supercapacitors., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (This journal is © The Royal Society of Chemistry.)

Silicon is a worthy substitute anode material for lithium-ion batteries because it offers high theoretical capacity and low working potentials vs. Li + /Li. However, immense volume changes and the low intrinsic conductivity of Si hampers its practical applications. In this study, nano/micro silicon particles are achieved by ball milling silicon mesh powder as a scalable process. Subsequent metal (Cu/Fe/Mn) doping into nano/micro silicon by low-temperature annealing, followed by high-temperature annealing with graphite, gives a metal-doped silicon/graphite composite. The obtained composites were studied as anodes for Li-ion batteries, and they delivered high reversible capacities of more than 1000 mAh g -1 with improved Li + diffusion properties. The full cells from these composite anodes vs. LiCoO 2 cathodes delivered suitable energy densities for Li + storage applications. The enhanced electrochemical properties are accredited to the synergistic effect of metal doping and graphite addition to silicon and exhibit potential for suitable Li + energy storage applications.