In this study we have investigated the electrochemical properties of hollow silicon nanospheres encapsulated with a thin carbon shell, HSi@C, as a potential candidate for lithiumion battery anodes. Hollow Si nanospheres are formed using a templating method which is followed by carbon coating via carbonization of a pyrrole precursor to form HSi@C. The synthesis conditions and the resulting structure of HSi@C have been studied in detail to obtain the target design of hollow Si nanospheres encapsulated with a carbon shell. The HSi@C obtained exhibits much better electrochemical cycle stability than both micro-and nano-size silicon anodes and deliver a stable specific capacity of 700 mA h g-1 after 100 cycles at a current density of 2 A g-1 and 800 mA h/g after 120 cycles at a current density of 1 A g-1. The superior performance of HSi@C is attributed to the synergistic combination of the nanostructured material, the enhanced conductivity, and the presence of the central void space for Si expansion with little or no change in the volume of the entire HSi@C particle. This study is the first detailed investigation of the synthesis conditions to attain the desired structure of a hollow Si core with a conductive carbon shell. This study also offers guidelines to further enhance the specific capacity of HSi@C anodes in the future.
Li3BN2 is investigated for the first time as a transition metal free, high capacity cathode material for Li‐ion batteries. It is shown that α‐Li3BN2 can exhibit a specific capacity of 890 mA h g−1 with the charge storage mechanism associated with the valence state change of N ions in the BN2 anion. The specific capacity demonstrated in this study is the highest one ever reported in literature for an intercalation‐type cathode material. Further, using the valence state change of N ions as a charge storage mechanism opens the door for designing additional high performance, transition metal free electrodes in the future.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.