MultipleAnionic Transition-Metal Oxycarbide for BetterLithium Storage and Facilitated Multielectron Reactions

As an important class of mutlielectron reaction materials, the applications of transition-metal oxides (TMOs) are impeded by volume expansion and poor electrochemical activity. To address these intrinsic limitations, the renewal of TMO inspires research on incorporating an advanced interface layer with multiple anionic characteristics, which may add functionality to support properties inaccessible to single-anion TMO electrode. Herein, transition metal oxycarbide (TMOC, M=Mo) with more than one anionic species was prepared as an interface layer on corresponding oxide. Multiple anionic TMOC possesses advantages of structural stability, abundant active sites and elevated metal cation valence states. Such merits mitigate volume changes and enhance multielectron reaction significantly. TMOC nanocomposite has well-maintained capacity after 1000 cycles at 2 A·g-1 and fully resumed rate performance. In-situ synchrotron X-ray powder diffraction (SXRPD) analysis unveils negligible volume expansions occurring upon ...