MOF-Derived Mn₃O₄@C Hierarchical Nanospheres as Cathodes for Aqueous Zinc-Ion Batteries

Abstract

Aqueous zinc-ion batteries are potential electrochemical storage systems due to their safety, low cost, senior energy density, and environmental friendliness. There are no suitable cathode materials with cyclic stability due to the high polarization of Zn2+ ions, so synthesizing cathode materials with excellent electrochemical performance is still a problem to be solved. Mn3O4 is a potential cathode material owing to its abundant valence states. Nevertheless, it has poor cycling performance due to the disproportionation effect of Mn2+. Herein, we synthesize Mn3O4@C hierarchical nanospheres successfully using a Mn metal–organic framework via a simple hydrothermal synthesis method combined with a heat treatment process. Benefiting from the carbon coating, the Mn3O4@C cathode has a higher specific capacity of 331.5 mAh g–1 at 0.2 A g–1 (124.3 mAh g–1 at 3.0 A g–1) and satisfactory cyclic stability after 1900 cycles. The energy storage mechanism of insertion/extraction of H+ and Zn2+ is investigated by ex situ X-ray photoelectron spectroscopy. These results demonstrate a strategy to improve the manganese oxide cathode by the carbon coating for aqueous zinc-ion batteries.

Flower-Like Ni–Mn Bimetallic Oxide-Based Nanosheets for Enhanced Electrocatalytic Nitrogen Reduction to Ammonia

“…Figure d shows the XPS spectrum of Mn 2p. , Considering that Mn 2p 1/2 with a binding energy close to Ni 2p is susceptible to interference, we mainly resolve Mn 2p 3/2 . The peaks of Mn 2p at 637.3, 641.4, and 642.9 eV corresponded to Mn 0 , Mn 2+ , and Mn 3+ , respectively. − These results demonstrate that Mn species on the surface of NiMnO x -3@CC may be present in mixed valences.…”

Rice powder template for hausmannite Mn3O4 nanoparticles and its application to aqueous zinc ion battery

“…With increasing of scan rates the peak heights of peak1, peak2 and peak3, as labelled in Fig 8(A) , increased. High scan rate increases the reaction rate thereby quickens the electron transfer process [ 10 ]. From this result, probable reaction could be given as- …”

“…Although V-based cathode materials delivers high capacity and long cycling rate of performance, but they are costly, poisonous, and have a low voltage of operation (0.6–0.9 V). Likewise, cathode materials having organic framework have high value of specific capacity, but poor conductivity and low operating voltage [ 10 , 11 ]. On the contrary, Mn-based cathode materials, with polymorphs or different crystal structure (α-, β-, δ-, γ-, λ-, T-type, R-type, ε- MnO 2 ) and oxidation states (MnO, Mn 2 O 3, and Mn 3 O 4 ), have gained the most attention of the researchers for their high specific capacity (308 mAhg -1 ), cost effectiveness, non toxicity, and high operating voltage (1.2–1.5 V) than Zn anodes [ 12 , 13 ].…”

Photo-thermal coupling to enhance CO2 hydrogenation toward CH4 over Ru/MnO/Mn3O4

“…Apart from metal centers, the support also plays a critical role in CO 2 hydrogenation by influencing the geometric and electronic properties of active sites. Particularly, MnO x is considered a promising support for hydrogenation reactions due to some obvious advantages 19 . It is worth of noting that the multiple valences and reducible effect of MnO x confers flexible mediation capability on the catalysts 20 .…”