All-solid-state lithium batteries (ASSLBs) are considered promising next-generation energy storage devices due to their safety and high volumetric energy densities. However, achieving the key U.S. DOE milestone of a power density of 33 kW L −1 appears to be a significant hurdle in current ASSLBs. One of the main reasons is that advancements in solid electrolyte (SE) conductivity have been prioritized over the critical current density (CCD) when employing an elemental Li anode. Several aspects of Li electrode-and SE interface-based difficulties must be resolved before commercialization. Here, we very deeply analyze some crucial parameters that effectively restrict Li dendrite formation while achieving high CCD. Mechanistic explanations are provided to comprehend the critical relationship between a cell failure and development of Li dendrites. The latest progress is discussed in achieving higher CCD in emerging SE structures, including Li-stuffed garnets, Na superionic conductors (NASICONs), Li sulfides, and lithium phosphorus oxynitride (LiPON). Furthermore, primary strategies for improving CCDs by tailoring SE design and stabilizing interfaces are proposed for advanced ASSLBs.

An effective modulation of the active sites in a bifunctional electrocatalyst is essentially desired, and it is a challenge to outperform the state-of-the-art catalysts toward oxygen electrocatalysis. Herein, we report the development of a bifunctional electrocatalyst having target-specific Fe–N4/C and Co–N4/C isolated active sites, exhibiting a symbiotic effect on overall oxygen electrocatalysis performances. The dualism of N-dopants and binary metals lower the d-band centers of both Fe and Co in the Fe,Co,N–C catalyst, improving the overpotential of the overall electrocatalytic processes (ΔE ORR‑OER = 0.74 ± 0.02 V vs RHE). Finally, the Fe,Co,N–C showed a high areal power density of 198.4 mW cm–2 and 158 mW cm–2 in the respective liquid and solid-state Zn–air batteries (ZABs), demonstrating suitable candidature of the active material as air cathode material in ZABs.

Interconnected conducting porous graphene as supercapacitive material as well as current collector for integrated metal-free microsupercapacitor (MSC) having ultra-long cycle life and outstanding capacitive performance.

Here we report on the magnetic properties of iron carbide nanoparticles embedded in a carbon matrix. The granular distribution of nanoparticles in an inert matrix, of potential use in various application, were prepared by pyrolysis of organic precursors using thermal assisted chemical vapour deposition method. By varying the precursor concentration and preparation temperature, compositions with varying iron concentration and nanoparticle sizes were made. Powder X-ray diffraction, Transmission Electron Microscopy and Mössbauer spectroscopy studies revealed, the nanocrystalline iron carbide (Fe 3 C) presence in the partially-graphitized matrix. The dependence of magnetic properties on the particle size and temperature (10 K

The rational design of electronically tuned transition-metal-doped conductive carbon nanostructures has emerged as a potential substitution of a platinum-group-metal (PGM)-free electrocatalyst for oxygen reduction reaction (ORR). We report here a universal strategy using a one-step thermal polymerization reaction for transition-metal-doped graphitic carbon nitride (g-C3N4) without any conductive carbon support as a highly efficient ORR electrocatalyst. X-ray absorption spectroscopy evidences the presence of Fe–Nx active sites with a possible three-coordinated Fe atom with N atoms. The as-prepared Fe-g-C3N4 with improved surface area, graphitic nature, and conductive carbon framework exhibits a superior electrochemical performance toward ORR activity in an alkaline medium. Interestingly, it displays a 0.88 V (vs reversible hydrogen electrode, RHE) half-wave potential (E 1/2) with a four-electron-transfer pathway and excellent stability outperforming platinum/carbon (Pt/C) in an alkaline medium. More impressively, when the Fe-g-C3N4 catalyst is used as a cathode material in a zinc–air battery, it presents a higher peak power density (148 mW cm–2) than Pt/C (133 mW cm–2), which further established the importance of the low-cost material synthesis approach toward the development of an earth-abundant PGM-free catalyst for fuel-cell and air battery fabrication.