A Double‐Buffering Strategy to Boost the Lithium Storage of Botryoid MnOx/C Anodes. Issue 16 (29th March 2019) - Yang, Cheng
Abstract: Transition metal oxides (TMOs) are regarded as promising candidates for anodes of lithium ion batteries, but their applications have been severely hindered by poor material conductivity and lithiated volume expansion. As a potential solution, herein is presented a facile approach, by electrospinning a manganese‐based metal organic framework (Mn‐MOF), to fabricate yolk–shell MnO x nanostructures within carbon nanofibers in a botryoid morphology. While the yolk–shell structure accomodates the lithiated volume expansion of MnO x, the fiber confinement ensures the structural integrity during charge/discharge, achieving a so‐called double‐buffering for cyclic volume fluctuation. The formation mechanism of the yolk–shell structure is well elucidated through comprehensive instrumental characterizations and cogitative control experiments, following a combined Oswald ripening and Kirkendall process. Outstanding electrochemical performances are demonstrated with prolonged stability over 1000 cycles, boosted by the double‐buffering design, as well as the "breathing" effect of lithiation/delithiation witnessed by ex situ imaging. Both the fabrication methodology and electrochemical understandings gained here for nanostructured MnO x can also be extended to other TMOs toward their ultimate implementation in high‐performance lithium ion batteries (LIBs). Abstract : Botryoid binder‐free lithium ion battery anodes composed of yolk–shell MnO x nanoparticles confined in nitrogen‐doped carbonized nanofibers are fabricated by electrospinning manganese‐based metal organic frameworks. This hierarchical architecture provides double buffering for cyclic volume fluctuation during charge/discharge, ensuring the structural stability and integrity of the composite electrode toward prolonged lithium storage performance.