A carbon-coated spinel zinc cobaltate doped with manganese and nickel as a cathode material for aqueous zinc-ion batteries

Here, a new amorphous material composed of carbon-coated zinc cobaltate doped with manganese and nickel ZNMC@C (ZnNi_0.5Mn_0.5CoO₄@C) with a spinel structure is proposed as a cathode material for use in aqueous zinc-ion batteries. This cathode material exhibits a high charge/discharge capacity with an initial capacity of about 160 mA h g^-1 and its capacity retention rate remains at 60% after 500 cycles at 0.2 A g^-1, which is higher than that of some reported spinel cathode materials. This superior electrochemical performance can be ascribed to the synergistic effect of the co-doping of manganese and nickel, which produces reversible multivalence redox transition activity (Co⁴⁺/Co³⁺, Ni⁴⁺/Ni³⁺/Ni²⁺, and Mn⁴⁺/Mn³⁺) that facilitates the insertion and migration of zinc ions and the existence of an outer amorphous carbon coating that effectively inhibits the dissolution of the cathode structure and stabilizes the cathode structure. In addition, the cycling mechanism of ZNMC@C was analyzed in detail through electrochemical measurements of the different cycling stages, including the kinetic behavior based on cyclic voltammetry and electrochemical impedance spectroscopic analysis and the reaction mechanism from X-ray photoelectron spectroscopy, ex situ X-ray diffractometry and ex situ scanning electron microscopy analysis. These research results suggest that the ZNMC@C composite material could be a competitive cathode material for Abs (aqueous rechargeable batteries).

Carbon Nanotubes Coupled with Metal Ion Diffusion Layers Stabilize Oxide Conversion Reactions in High-Voltage Lithium-Ion Batteries

Creating new architectures combined with super diverse materials for achieving more excellent performances has attracted great attention recently. Herein, we introduce a novel dual metal (oxide) microsphere reinforced by vertically aligned carbon nanotubes (CNTs) and covered with a titanium oxide metal ion-transfer diffusion layer. The CNTs penetrate the oxide particles and buffer structural volume change while enhancing electrical conductivity. Meanwhile, the external TiO₂-C shell serves as a transport pathway for mobile metal ions (e.g., Li⁺) and acts as a protective layer for the inner oxides by reducing the electrolyte/metal oxide interfacial area and minimizing side reactions. The proposed design is shown to significantly improve the stability and Coulombic efficiency (CE) of metal (oxide) anodes. For example, the as-prepared MnO-CNTs@TiO₂-C microsphere demonstrates an extremely high capacity of 967 mA h g^-1 after 200 cycles, where a CE as high as 99% is maintained. Even at a harsh rate of 5 A g^-1 (ca. 5 C), a capacity of 389 mA h g^-1 can be maintained for thousands of cycles. The proposed oxide anode design was combined with a nickel-rich cathode to make a full-cell battery that works at high voltage and exhibits impressive stability and life span.

MnO@graphene nanopeapods derived via a one-pot hydrothermal process for a high performance anode in Li-ion batteries

Although transition metal oxide-carbon (TMO-C) composites exhibit high Li storage capacity, the weak bonding between TMO particles and carbon mainly via van der Waals' force and the limited internal void space result in poor rate capability and cycling performance. Herein, MnO@graphene nanopeapods are produced by calcination of hydrothermally-synthesized MnO2-C composites. The flexible graphene shells provide superior conductivity and excellent structural stability to the MnO cores, and the enough internal void space can significantly buffer the drastic volume expansion. The MnO@graphene nanopeapods exhibit high Li storage capacity (1168 mA h g-1 at 50 mA g-1 and 945 mA h g-1 at 500 mA g-1) at a voltage platform of ∼1.2 V, excellent rate capability (728 mA h g-1 at 1000 mA g-1 and 505 mA h g-1 at 3000 mA g-1), high initial coulombic efficiency (85.9%) and remarkable long-life cycling performance (undiminished after 1000 cycles). The MnO@graphene nanopeapods have been successfully used as the anode to assemble a full battery with LiFePO4 as the cathode. Our results provide a useful and rational strategy to design high performance graphene-supported MnO composites for Li ion batteries.

Preparation of novel two-stage structure MnO micrometer particles as lithium-ion battery anode materials

MnO micrometer particles with a two-stage structure (composed of mass nanoparticles) were produced via a one-step hydrothermal method using histidine and potassium permanganate (KMnO₄) as reagents, with subsequent calcination in a nitrogen (N₂) atmosphere.

Fast Preparation of Porous MnO/C Microspheres as Anode Materials for Lithium-Ion Batteries

Porous MnO/C microspheres have been successfully fabricated by a fast co-precipitation method in a T-shaped microchannel reactor. The structures, compositions, and electrochemical performances of the obtained MnO/C microspheres are characterized by X-ray diffraction, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller analysis, charge-discharge testing, cyclic voltammograms, and electrochemical impedance spectra. Experimental results reveal that the as-prepared MnO/C, with a specific surface area of 96.66 m²·g^-1 and average pore size of 24.37 nm, exhibits excellent electrochemical performance, with a discharge capacity of 655.4 mAh·g^-1 after cycling 50 times at 1 C and capacities of 808.3, 743.7, 642.6, 450.1, and 803.1 mAh·g^-1 at 0.2, 0.5, 1, 2, and 0.2 C, respectively. Moreover, the controlled method of using a microchannel reactor, which can produce larger specific surface area porous MnO/C with improved cycling performance by shortening lithium-ion diffusion distances, can be easily applied in real production on a large scale.

Facile synthesis of porous manganese oxide/carbon composite nanowires for energy storage

We proposed a facile in situ fabrication strategy for preparing porous MnO/C composite nanowires by one-step carbonization of manganese-based coordination polymer nanowires precursor.

MnO nanocrystals incorporated in a N-containing carbon matrix for Li ion battery anodes

In this study, MnO nanocrystals incorporated in a N-containing carbon matrix were fabricated by the facile thermal decomposition of manganese nitrate-glycine gels.

Three-Dimensional (3D) Bicontinuous Hierarchically Porous Mn2O3 Single Crystals for High Performance Lithium-Ion Batteries

Bicontinuous hierarchically porous Mn₂O₃ single crystals (BHP-Mn₂O₃-SCs) with uniform parallelepiped geometry and tunable sizes have been synthesized and used as anode materials for lithium-ion batteries (LIBs). The monodispersed BHP-Mn₂O₃-SCs exhibit high specific surface area and three dimensional interconnected bimodal mesoporosity throughout the entire crystal. Such hierarchical interpenetrating porous framework can not only provide a large number of active sites for Li ion insertion, but also good conductivity and short diffusion length for Li ions, leading to a high lithium storage capacity and enhanced rate capability. Furthermore, owing to their specific porosity, these BHP-Mn₂O₃-SCs as anode materials can accommodate the volume expansion/contraction that occurs with lithium insertion/extraction during discharge/charge processes, resulting in their good cycling performance. Our synthesized BHP-Mn₂O₃-SCs with a size of ~700 nm display the best electrochemical performance, with a large reversible capacity (845 mA h g⁻¹ at 100 mA g⁻¹ after 50 cycles), high coulombic efficiency (>95%), excellent cycling stability and superior rate capability (410 mA h g⁻¹ at 1 Ag⁻¹). These values are among the highest reported for Mn₂O₃-based bulk solids and nanostructures. Also, electrochemical impedance spectroscopy study demonstrates that the BHP-Mn₂O₃-SCs are suitable for charge transfer at the electrode/electrolyte interface.

MOF-derived ultrafine MnO nanocrystals embedded in a porous carbon matrix as high-performance anodes for lithium-ion batteries

Although MnO has been demonstrated to be a promising anode material for lithium-ion batteries (LIBs) in terms of its high theoretical capacity (755 mA h g(-1)), comparatively low voltage hysteresis (<0.8 V), low cost, and environmental benignity, the application of MnO as a practical electrode material is still hindered by many obstacles, including poor cycling stability and huge volume expansion during the charge/discharge process. Herein, we report a facile and scalable metal-organic framework-derived route for the in situ fabrication of ultrafine MnO nanocrystals encapsulated in a porous carbon matrix, where nanopores increase active sites to store redox ions and enhance ionic diffusivity to encapsulated MnO nanocrystals. As an anode material for lithium-ion batteries (LIBs), these MnO@C composites exhibited a high reversible specific capacity of 1221 mA h g(-1) after 100 cycles at a current density of 100 mA g(-1). The excellent electrochemical performance can be attributed to their unique structure with MnO nanocrystals dispersed uniformly inside a porous carbon matrix, which can largely enhance the electrical conductivity and effectively avoid the aggregation of MnO nanocrystals, and relieve the strain caused by the volumetric change during the charge/discharge process. This facile and economical strategy will extend the scope of metal-organic framework-derived synthesis for other materials in energy storage applications.

Rechargeable Co3O4 porous nanoflake carbon nanotube nanocomposite lithium-ion battery anodes with enhanced energy performances

Multi-walled carbon nanotube nanocomposites intertwined with porous Co₃O₄ nanoflakes serve as lithium-ion battery anode materials with enhanced performances.

Pristine hollow microspheres of Mn2O3 as a potential anode for lithium-ion batteries

Ascorbic acid aided inside-out Ostwald ripening promotes the formation of Mn₂O₃ microspheres with a hollow interior surface that exhibits an appreciable capacity of 610 mA h g⁻¹, even after completing 100 cycles.

Ge@C core–shell nanostructures for improved anode rate performance in lithium-ion batteries

The Ge@C core–shell nanostructures exhibit excellent cycling performance and rate capability as an electrode material for lithium ion batteries.

Nanoflake driven Mn2O3 microcubes modified with cooked rice derived carbon for improved electrochemical behavior

Mn₂O₃ microcubes, symmetrically formed out of the systematic stacking of nanoflakes, built with nanoparticles in the 30–50 nm range have been obtained from a simple co-precipitation method.

MOF-derived self-assembled ZnO/Co3O4 nanocomposite clusters as high-performance anodes for lithium-ion batteries

Although different kinds of metal oxide nanoparticles are extensively investigated as anode materials for lithium-ion batteries (LIBs), their cycle life and energy/power density are still not suitable for commercial applications.

Carbon coated manganese monoxide octahedron negative-electrode for lithium-ion batteries with enhanced performance

Carbon coated MnO octahedra with narrow size distribution and good dispersity have been fabricated and applied as lithium ion battery anode materials.