Multi-Yolk–Shell MnO@Carbon Nanopomegranates with Internal Buffer Space as a Lithium Ion Battery Anode

Abstract

Multi-yolk–shell MnO@mesoporous carbon (MnO@m-carbon) nanopomegranates, featuring MnO nanoparticles within cavities of m-carbon with internal space between the MnO nanoparticle and a cavity carbon shell, were subtly constructed. Moreover, the buffer space was well controlled by means of regulating the size of the cavity in m-carbon or the content of MnO. The results of electrochemical measurements demonstrated that MnO(10)@m-carbon(22) nanopomegranates (MnO nanoparticle, 15 nm; cavity size, 22 nm) had the best cycling and rate performance for lithium ion storage. The pomegranate-like MnO@m-carbon nanostructures have shown several advantages for their excellent performance: the nanocavity in m-carbon can restrict the growth and agglomeration of MnO nanoparticles; the well-interconnected mesoporous carbon matrix provides a “highway” for electrons and lithium ion transport; the voids between the MnO nanoparticle and cavity shell can alleviate the volume expansion.

Highly Reversible Li‐Ion Full Batteries: Coupling Li‐Rich Li1.20Ni0.28Mn0.52O2 Microcube Cathodes with Carbon‐Decorated MnO Microcube Anodes

“…The as‐obtained porous MnO@C MCs could have the following structural advantages when applied to the LIB anodes (i) The porous structure of MnO@C MCs enables efficient Li + diffusion for an enhanced kinetic property [32] . (ii) Carbon shells on the MnO MCs surface could increase electronic conductivity [23] . (iii) The porous MnO@C MCs could also buffer the volume changes during charge/discharge reactions [18] …”

“…These impressive electrochemical properties of MnO@C MCs might be related to the following architectural features: (i) Coated‐carbon shells and their porous architecture could improve the electric conductivity of the electrode [18] . (ii) Porous structure of MnO@C MCs could increase electrolyte/electrode contact areas for faster Li + diffusion [23] . Consequently, the full LIB consisting of LLNMO cathode and MnO@C anode could deliver the high discharge capacity of 149.2 mAh g −1 at the first cycle.…”

“…[18] (ii) Porous structure of MnO@C MCs could increase electrolyte/ electrode contact areas for faster Li + diffusion. [23] Consequently, the full LIB consisting of LLNMO cathode and MnO@C anode could deliver the high discharge capacity of 149.2 mAh g À 1 at the first cycle.…”

“…[20][21][22] In the case of the anode active materials, transition-metal oxides have received great attention for replacing currently commercialized graphite anode materials due to their high capacity, environmental benignity, and low cost. [23,24] As prospective anode materials, MnO has been studied widely because of its high theoretical specific capacity (756 mAh g À 1 ), safety, and environmental friendliness among the various transition-metal oxides. [25,26] However, the electrode cycling reversibility of MnO still remains a problem to be solved for application to commercial LIB anodes due to its low electrical conductivity and large volume changes during cycling, which results in a capacity reduction associated with the electrode pulverization.…”

In situ formation of MnO@N-doped carbon for asymmetric supercapacitor with enhanced cycling performance

“…6 Prepared via simple ultrasonication followed by calcination treatments, MnO@carbon nanopipes with core-shell structure presented prominent electrochemical performance for both supercapacitor and lithium ion battery. 7 In addition, MnO@carbon composites with other structures have also been reported in recent years, such as MnO@biomass-inherited porous carbon, 8 N-doped graphitic carbon (NC)-encapsulated MnO-Co heterostructure, 9 core-shell MnO@C, 10 carbon-anchored MnO nanosheets, 11 multi-yolk-shell MnO@mesoporous carbon, 12 multicore-shell MnO@N-doped carbon nanocapsule, 13 hierarchically MnO@C microsphere, 14 and so on. The other solution is the design of porous structure to buffer the volume variation, improving cycling performance.…”