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Solid electrolytes are pivotal in ushering in the new era of energy technology, offering fresh prospects for its advancement. Recently, halide solid electrolytes have garnered significant attention due to their wide electrochemical window, high lithium ion conductivity at room temperature (RT), and high stability to the positive electrode. In particular, a promising LaCl3-based solid-state electrolyte (SSE) with a non-close-packed structure could provide abundant one-dimensional (1D) channels for lithium ions, and it is compatible with lithium metal. However, the 1D channels are easily blocked by defects, and doping with several high-cost elements on the La site has been reported to optimize the migration path. Therefore, there is an imperative need to devise innovative strategies to further enhance the properties of LaCl3-based SSEs and to expand the LaCl3-based material family. Here, we report a cost-effective Zr4+ and O2− co-doping LaCl3-based oxychloride Li+ superionic conductor (Li0.5+xZr0.25La0.5Cl3−xOx). The sample with the optimized composition, Li0.8Zr0.25La0.5Cl2.7O0.3, exhibits a high ionic conductivity of 0.75 mS cm−1 at room temperature, a low activation energy of 0.23 eV, and remarkable compatibility with Li metal. The critical current density attains a high value of 7 mA cm−2, and the long-term cycling of Li–Li symmetric cells experiences the stable plating/striping process under 0.1 mA cm−2 and 3 mA cm−2. Furthermore, the all-solid-state battery with the LiCoO2 composite cathode delivers commendable cycling performance at 0.2C and 0.5C. [ABSTRACT FROM AUTHOR]

Bimetallic carbides have aroused wide attention for energy-storage applications recently. In this work, one-dimensional Fe 2 MoC/CNFs (Fe 2 MoC/C nanofibers) are successfully synthesized via a facile electrospinning method for the first time. To obtain the most integrated structure between the Fe 2 MoC nanoparticles and carbon nanofibers, we explore the optimal heating rate during the carbonization treatment. Fe 2 MoC/CNFs exhibits an integrated one-dimensional structure under 800 °C with a heating rate of 5 °C/min. As revealed in the experimental results, Fe 2 MoC/CNFs possesses a high specific surface area of 196.9 m2/g, a high specific capacitance of 347.8 F/g at the current density of 1 A/g, an excellent rate capability of 91% capacitance retention from 1 A/g to 40 A/g, and shows superior cycling stability with the capacitance retention of about 85.6% and Coulombic efficiency of about 100% after 5000 cycles. An asymmetric supercapacitor coin-cell device using Fe 2 MoC/CNFs as the positive electrode displays an energy density of 14.5 Wh/kg at a power density of 300 W/kg and an outstanding cycling life of 93% retention after 5000 cycles. The impressive electrochemical performance indicates that the Fe 2 MoC/CNFs composite is a promising material for efficient supercapacitors. Image 1 • Fe 2 MoC nanofibers can be prepared via a facile electrospinning method. • Fe 2 MoC/CNFs-5 exhibits a superior rate capability and cycle stability. • ASC coin-cell device shows a promising energy and power density. [ABSTRACT FROM AUTHOR]

Morphology of transition metal oxide largely affects its electrochemical energy storage properties. This also applies to its composites. In this paper, NiFe 2 O 4 /Graphene nanosheets composites (NFO/GNSs) are successfully prepared by a facile hydrothermal method. NiFe 2 O 4 (NFO) in the sample exhibits a unique nanosheet morphology, vertically arranging on the graphene nanosheets (GNSs). Microscopically, NFO nanosheets interpenetrate on the surface of graphene to form a continuous network structure. The sample exhibits excellent specific capacitance and rate performance. It is worth mentioning that the specific capacitance increases to 140% after 5000 cycles, showing superior cycle stability. This may be due to the conductive network formed by NFO nanosheets and GNSs. Excellent electrochemical performance indicates excellent application prospects of materials in supercapacitor electrodes. Image 1 • Unique NiFe 2 O 4 nanosheets structure with graphene nanosheets was successfully prepared by a hydrothermal method. • NiFe 2 O 4 nanosheets/graphene performed a better specific capacitance, arriving at 464.15 F/g at current density of 1 A/g. • The network structure formed between NiFe 2 O 4 nanosheets and graphene nanosheets provides excellent cycle performance. [ABSTRACT FROM AUTHOR]

Sulfide all-solid-state lithium battery (ASSLB) with nickel-rich layered oxide as the cathode is promising for next-generation energy storage system. However, the Li + transport dynamic and stability in ASSLB are hindered by the structural mismatches and the instabilities especially at the oxide cathode/sulfide solid electrolyte (SE) interface. In this work, we have demonstrated a simple and highly effective solid-state mechanofusion method (1500 rpm for 10 min) to combine lithium conductive NASICON-type LiZr 2 (PO 4 ) 3 nanocrystals (∼20 nm) uniformly and compactly onto the surface of the single crystallized LiNi 0.8 Co 0.1 Mn 0.1 O 2 , which can also attractively achieve Zr 4+ doping in NCM811 and oxygen vacancies in the LZPO coating without solvent and annealing. Benefiting from the alleviated interface mismatches, sufficient Li + ion flux through the LZPO coating, promoted structural stabilities for both NCM811 and sulfide SE, strong electronic coupling effect between the LZPO and NCM811, and enlarged (003) d -spacing with enriched Li + migration channels in NCM811, the obtained LZPO-NCM811 exhibits superior stability (185 mAh/g at 0.1C for 200 cycles) and rate performance (105 mAh/g at 1C for 1300 cycles) with high mass loading of 27 mg NCM /cm 2 in sulfide ASSLB. Even with a pronounced 54 mg NCM /cm 2 , LZPO-NCM811 manifests a high areal capacity of 9.85 mAh/cm 2 . The convenient and highly effective interface engineering strategy paves the way to large-scale production of various coated cathode materials with synergistic effects for high performance ASSLBs.

As an M n+1 AX n phase ternary layered carbide, Ti₃SiC₂ possesses the advantages of both excellent stability and high electrical conductivity, which are considered to be promising electrode materials for supercapacitors. Ti₃SiC₂/Carbon nanofiber composites with one-dimensional nanostructures were successfully synthesized via electrospinning. Systematic electrochemical tests showed that the Ti₃SiC₂/Carbon composite possesses a large specific capacitance of 133.1 F/g at the current density of 1 A/g, high rate capability of 113.7% capacitance retention from 1 to 10 A/g, and low resistance of 1.07 Ω. After assembling the asymmetrical supercapacitor, Ti₃SiC₂/Carbon provides the energy density of 7.02 Wh/kg at the power density of 140 W/kg. In addition, Ti₃SiC₂/Carbon composite is highly stable, with 74.6% capacity retention after 4000 cycles. Ti₃SiC₂/Carbon's superior electrochemical properties are ascribed to the 1D nanowire structure and the high specific surface area. Ti₃SiC₂/Carbon is a prospective electrode material for future supercapacitors.