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Iron (III) fluoride (FeF 3), characterized by high voltage and high specific capacity and emerges as a promising candidate for the forthcoming generation of cathode materials in lithium-ion batteries. This study employs a novel methodology by introducing Fe3+ sources into hollow acetylene black particles through a vacuum impregnation method. This innovative approach results in the synthesis of a composite material comprising FeF 3 ∙0.33H 2 O encapsulated within hollow acetylene black nanospheres, denoted as the FeF 3 ∙0.33H 2 O @hollow acetylene black nanosphere composite material (FF@HCN). The composite exhibits a shell composed of highly graphitized carbon and a core containing FeF 3 ∙0.33H 2 O particles in the range of 10–20 nm. The proportion of active materials is 75.56 %. The acetylene black has chain-like structure and high specific surface area, significantly enhances the material's conductivity, contributing 74.4 % to the pseudocapacitance at a scan rate of 1 mV s−1. The cavity graphite shell plays a crucial role in restricting the expansion and pulverization decay of FeF 3 ∙0.33H 2 O nanoparticles, thereby markedly improving the cycle stability. The initial capacity of the FF@HCN composite is 224.4 mAh g−1, and after 1000 cycles at 0.1 C , it maintains a capacity of 162.3 mAh g−1, resulting in a capacity retention rate of 72.3 % and decay per cycle of 0.027 %. A composite material comprising FeF 3 •0.33H 2 O encapsulated within hollow acetylene black nanosphere are successfully synthesized by vacuum impregnation. The highly graphitized carbon shell in the yolk-shell structured composite play a key role in constraining FeF 3 •0.33H 2 O particle pulverization and improving charge transfer, which slows down the capacity decay as well as accelerates the reaction kinetics. [Display omitted] • FeF 3.•0.33H 2 O encapsulated within hollow acetylene black nanosphere are successfully synthesized by vacuum impregnation. • The decreasing of particle pulverization significantly slows down the capacity decay as a cathode in lithium ion cell. • A capacity retention rate of 72.3 % after 1000 cycles is achieved. [ABSTRACT FROM AUTHOR]

The development of elastic nanostructured Si-based anodes holds promise for advancing lithium-ion batteries due to the high theoretical specific capacity exhibited by Si. Combining nanostructured Si with C proves to be a successful strategy in addressing the challenges tied to the substantial volume expansion of Si during lithiation. In this work, a novel Si-based anode is fashioned through a simple and universal strategy, integrating Si nanoparticles with 1D nano-carbonaceous fillers (CPPy-NT) featuring nanotubular morphology and N atoms, and a water-based binder (poly(acrylic acid)). CPPy-NT are derived by carbonizing pre-synthesized polypyrrole nanotubes (PPy-NT). A clear correlation is established among the carbonization temperature for CPPy-NT preparation, N content in CPPy-NT, electrical conductivity, and the electrochemical performance of the ensuing Si/CPPy-NT anode. For comparative analysis, the electrochemical properties of the Si-based anode employing Super P (commercial carbon black) or PPy-NT are contrasted with those of Si/CPPy-NT. Notably, the Si/CPPy-NT anode with CPPy-NT bearing the highest amount of graphitic N sites exhibits a substantial improvement in initial charge capacity (approximately 2200 mAh g−1) and enhanced cycling stability. These findings underscore the potential to elevate the electrochemical activity of the C filler by carefully optimizing morphology, conductivity, and the incorporation of an appropriate amount of graphitic N. [Display omitted] • Synthesis of N-containing 1D nano-carbonaceous fillers with tailored properties. • Integration of N-containing 1D nano-carbonaceous fillers in Si-based anodes. • Development of novel Si/C anodes using an environmentally friendly approach. • Beneficial role of N in enhancing the electrochemical properties of Si/C anodes. [ABSTRACT FROM AUTHOR]