MnCo₂S₄‐CoS_1.097 Heterostructure Nanotubes as High Efficiency Cathode Catalysts for Stable and Long‐Life Lithium‐Oxygen Batteries Under High Current Conditions

Abstract

Constructing the heterostructures is considered to be one of the most effective methods to improve the poor electrical conductivity and insufficient electrocatalytic properties of metal sulfide catalysts. In this work, MnCo 2 S 4 -CoS 1.097 nanotubes are successfully prepared via a refluxhydrothermal process. This novel cathode catalyst delivers high discharge/charge specific capacities of 21 765/21 746 mAh g −1 at 200 mA g −1 and good rate capability. In addition, a favorable cycling stability with a fixed specific capacity of 1000 mAh g −1 at high current density of 1000 mA g −1 (167 cycles) and 2000 mA g −1 (57 cycles) are delivered. It is proposed that fast transmission of ions and electrons accelerated by the built-in electric field, multiple active sites from the heterostructure, and nanotube architecture with large specific surface area are responsible for the superior electrochemical performance. To some extent, the rational design of this heterostructured metal sulfide catalyst provides guidance for the development of the stable and efficient cathode catalysts for Li-O 2 batteries that can be employed under high current conditions.

Sandwich-like CoMoP2/MoP heterostructures coupling N, P co-doped carbon nanosheets as advanced anodes for high-performance lithium-ion batteries

“…Recently, heterostructures have been attracted a lot of attention in the research elds of photocatalysis [29], hydrogen evolution reaction (HER) [30] and water splitting [31], etc. It has been widely proved that with the distinct band gaps compounded in different components, the differences in Fermi energy levels combined together could build up an equilibrium of equal Fermi energy levels [32], thereby generating a space charge region, which could accelerate the charge transport and the interface reaction kinetics [33][34][35]. Enlightened by the unique architecture construction with different materials via physical and chemical combinations, heterostructures are desired to perfect the electrochemical properties for LIBs.…”

Three‐Dimensional Porous MnCo2S4 Microrugby Balls Supported on Carbon Cloth for Efficient Oxygen Evolution Reaction

“…In addition, the fitted peaks at 643.0 and 655.1 eV are indexed to Mn 3 + , and the peak at 645.9 eV is a satellite peak (identified as "Sat"), indicating the coexistence of Mn 2 + and Mn 3 + . [18,32] Similarly, in the Co 2p spectrum of MnCo 2 S 4 /CC (Figure 3c), the peak at 781.0 eV is Co 2p 3/2 and the other main peak at 796.0 eV are contributed to the Co 2p 1/2 . The fitted peaks with binding energy at 779.3 and 794.5 eV are ascribed to Co 3 + , while those at 781.4 and 797.5 eV are attributed to Co 2 + .…”

Rational Design of Space-Confined Mn-Based Heterostructures with Synergistic Interfacial Charge Transport and Structural Integrity for Lithium Storage

“…In addition to the incorporation of the carbon material and the heterostructure due to its unique synergistic effect, the built-in electric field established at the heterointerfaces of electrode materials with different energy band structures and compositions enhances the reaction kinetics at the heterogeneous interface and thus promotes the transport of charge carriers. , Additionally, a large number of defects and voids at the interface provide abundant electrochemical reaction active sites, which effectively improve the electrochemical performance of electrode materials. − In practice, transition metal oxides (TMOs) are usually used as the matrix material, and the corresponding sulfide is introduced into the oxide to form a heterostructure composite. ,− The transition metal sulfide (TMS) has a smaller band gap than the corresponding oxide (for example, the band gap of MnS is 3.7 eV while that of MnO is 4.2 eV), so it exhibits higher conductivity and a faster charge transfer rate, while the TMO has a higher theoretical specific capacity (756 mAh·g –1 for MnO, and 616 mAh·g –1 for MnS); therefore, TMO/TMS heterostructure composites can perfectly combine the respective advantages of sulfides and oxides. ,− …”