Coaxial MnO/C nanotubes as anodes for lithium-ion batteries

Synthesis of MnO/C/Co3O4 nanocomposites by a Mn2+-oxidizing bacterium as a biotemplate for lithium-ion batteries

The biotemplate and bioconversion strategy represents a sustainable and environmentally friendly approach to material manufacturing. In the current study, biogenic manganese oxide aggregates of the Mn²⁺-oxidizing bacterium Pseudomonas sp. T34 were used as a precursor to synthesize a biocomposite that incorporated Co (CMC-Co) under mild shake-flask conditions based on the biomineralization process of biogenic Mn oxides and the characteristics of metal ion subsidies. X-ray photoelectron spectroscopy, phase composition and fine structure analyses demonstrated that hollow MnO/C/Co₃O₄ multiphase composites were fabricated after high-temperature annealing of the biocomposites at 800°C. The cycling and rate performance of the prepared anode materials for lithium-ion batteries were compared. Due to the unique hollow structure and multiphasic state, the reversible discharge capacity of CMC-Co remained at 650 mAh g^-1 after 50 cycles at a current density of 0.1 Ag^-1, and the coulombic efficiency remained above 99% after the second cycle, indicating a good application potential as an anode material for lithium-ion batteries.

Synthesis of MnO/C/NiO-Doped Porous Multiphasic Composites for Lithium-Ion Batteries by Biomineralized Mn Oxides from Engineered Pseudomonas putida Cells

A biotemplated cation-incoporating method based on bacterial cell-surface display technology and biogenic Mn oxide mineralization process was developed to fabricate Mn-based multiphasic composites as anodes for Li-ion batteries. The engineered Pseudomonas putida MB285 cells with surface-immobilized multicopper oxidase serve as nucleation centers in the Mn oxide biomineralization process, and the Mn oxides act as a settler for incorporating Ni ions to form aggregates in this process. The assays using X-ray photoelectron spectroscopy, phase compositions, and fine structures verified that the resulting material MnO/C/NiO (CMB-Ni) was porous multiphasic composites with spherical and porous nanostructures. The electrochemical properties of materials were improved in the presence of NiO. The reversible discharge capacity of CMB-Ni remained at 352.92 mAh g^-1 after 200 cycles at 0.1 A g^-1 current density. In particular, the coulombic efficiency was approximately 100% after the second cycle for CMB-Ni.

MOF-derived manganese monoxide nanosheet-assembled microflowers for enhanced lithium-ion storage

Achieving high energy density, power density and cycling performance is a great challenge for lithium-ion battery (LIB) anodes. To obtain favorable electrochemical properties, an effective approach for designing composite nanomaterials with good stability and large specific surface area has been reported here. In this work, metal-organic framework (MOF)-derived manganese monoxides with a stable macromolecular framework were synthesized by utilizing the template agent 1,2,3,4-butanetetracarboxylic acid (BTCA) and the organic salt manganese acetylacetone, which possess a compact microflower structure assembled by nanosheets. As a synergistic effect, not only the amorphous carbon derived from MOFs enhances the specific capacity and stability, but also the unique nanosheet exhibits a significant nano-effect and high areal capacity, which is in favour of an electrochemical reaction. For further enhancement of the electrochemical performance, reduced graphene oxide (rGO) was introduced. When tested as a LIB anode, the MnO@rGO composite displays superior reversible capacities (1716 mA h g-1 at 0.1 A g-1 and 930 mA h g-1 at 2 A g-1) and remarkable rate performances. The research results of the composite nanomaterials lay a foundation for the fabrication of high-capacity and stable anode materials in LIBs.

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.

A critical role of catalyst morphology in low-temperature synthesis of carbon nanotube-transition metal oxide nanocomposite

The effect of the catalyst morphology on the growth of carbon nanotubes (CNT) on nanostructured transition metal oxides was investigated to study a novel low-temperature synthetic route to functional CNT-transition metal oxide nanocomposites. Among several nanostructured manganese oxides with various morphologies and structures, only exfoliated 2D nanosheets of layered MnO₂ acted as an effective catalyst for the chemical vapor deposition of CNT at low temperatures of 400-500 °C, which emphasizes the critical role of the catalyst morphology in CNT growth. Heat treatment of the MnO₂ nanosheets under a C₂H₂ flow induced the deposition of CNT, as well as a phase transition to a 2D ordered assembly of MnO nanoparticles. The resulting CNT-MnO nanocomposites displayed excellent functionalities in Li-ion electrodes with huge discharge capacities and good rate characteristics, which highlights the usefulness of the present method for studying functional CNT-metal oxide nanocomposites. Electron microscopy and density functional theory calculations propose a formation mechanism via the efficient adsorption of carbon on the MnO₂ nanosheets followed by the surface diffusion of carbon. It is of prime importance that the substitution of Fe for layered MnO₂ nanosheets remarkably improved the efficiency of the formation of CNT by enhancing the surface adsorption of carbon species. This is the first report of the efficient growth of CNT at a very low temperature of 400 °C. The universal merit of the 2D nanosheet morphology was confirmed by the successful synthesis of a CNT-TiO₂ nanocomposite with exfoliated titanate nanosheets. The present study demonstrates that employing exfoliated transition metal oxide nanosheets as catalysts provides an efficient low-temperature synthetic route to functional CNT-transition metal oxide nanocomposites.

A facile electrospinning and electrospraying synchronization technique for preparation of high performance MnO/C@rGO composite anodes for lithium storage

A facile electrospinning and electrospraying synchronization technique is used to assemble 1D nanowires with 2D graphene sheets to build as 3D MnO/C@rGO composite thin film. The raw material MnO₂powder was recovered from spent Zn/MnO₂batteries.

A scalable in situ surfactant-free synthesis of a uniform MnO/graphene composite for highly reversible lithium storage

A scalable in situ surfactant-free synthesis of a uniform MnO/graphene composite was prepared, and exhibited large reversible capacity with long-term and superior rate performance.

Halloysite clay nanotubes based phase change material composites with excellent thermal stability for energy saving and storage

Superhydrophobic halloysite clay nanotubes based PCM composites with excellent thermal stability have been fabricated. Taking advantage of the simple process and low cost, the composites may have great potential as solar energy storage systems.

SiO2–carbon nanocomposite anodes with a 3D interconnected network and porous structure from bamboo leaves

To seek for a low-cost, green and sustainable method of preparing nanostructured carbon electrode materials, we are inspired by natural biomaterials.

Designed construction and validation of carbon-free porous MnO spheres with hybrid architecture as anodes for lithium-ion batteries

A simple, cost-effective solution mediated oxidation strategy requiring no compositing additive has been used to engineer hierarchically formed carbon-free porous MnO spheres, validated as high capacity and high rate lithium-ion battery anode.

Fabrication of MnO/C composites utilizing pitch as the soft carbon source for rechargeable Li-ion batteries

MnO nanoparticles coated with pitch-derived soft carbon exhibit greatly enhanced electrochemical performance compared to those coated with glucose-derived hard carbon.

High Performance All-solid Supercapacitors Based on the Network of Ultralong Manganese dioxide/Polyaniline Coaxial Nanowires

In recent years, thin, lightweight and flexible solid supercapacitors are of considerable interest as energy storage devices. Here we demonstrated all-solid supercapacitors (SSCs) with high electrochemical properties, low self-discharge characteristics based on manganese dioxide/polyaniline (MNW/PANI) coaxial nanowire networks. The synergistic effect of MnO₂/PANI plus the unique coaxial nanostructure of the ultralong nanowires with a highly interconnected network effectively enhance the conductivity and capacitive performance of the SSCs device. The MNW/PANI composite with 62.5% MnO₂ exhibits an outstanding areal specific capacitance reaching 346 mF/cm² at 5 mV s⁻¹ which is significant higher than most previously reported solid supercapacitors (15.3 mF/cm²–109 mF/cm²) and is close to the that of the best graphene films solid state supercapacitors (372 mF/cm²). In contrast, only 190 mF/cm² of areal specific capacitance was obtained for the pure MnO₂ NW network. The supercapacitors also exhibited low leakage current as small as 20.1 μA, which demonstrated that the MNW/PANI SSCs have great potential for practical applications.

Nitrogen-Enriched Porous Carbon Coating for Manganese Oxide Nanostructures toward High-Performance Lithium-Ion Batteries

Manganese oxides are promising high-capacity anode materials for lithium-ion batteries (LIBs) yet suffer from short cycle life and poor rate capability. Herein, we demonstrate a facile in situ interfacial synthesis of core-shell heterostructures comprising nitrogen-enriched porous carbon (pN-C) nanocoating and manganese oxide (MnOx) nanotubes. When MnOx/pN-C serves as an anode material for LIBs, the pN-C coating plays multiple roles in substantially improving the lithium storage performance. In combination with the nanosized structure and nanotubular architecture, the MnOx/pN-C nanocomposites exhibit an impressive reversible capacity of 1068 mAh g(-1) at 100 mA g(-1), a high-rate delivery of 361 mAh g(-1) at 8 A g(-1), and a stable cycling retention up to 300 cycles. The surface pN-C coating strategy can be extended to design and fabricate various metal oxide nanostructures for high-performance LIBs.

Nanostructured Mn-based oxides for electrochemical energy storage and conversion

This review summarizes recent efforts made to use nanostructured Mn-based oxides for primary batteries, Li secondary batteries, metal–air batteries, and pseudocapacitors.

Integration of MnO@graphene with graphene networks towards Li-ion battery anodes

We have directly integrated MnO@graphene with graphene networks through the thermal decomposition of Mn–oleate complex in an argon atmosphere at high temperatures. The MnO/graphene composites exhibited superior cycling performance.

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.

MnO nanoparticles interdispersed in 3D porous carbon framework for high performance lithium-ion batteries

Interdispersed MnO nanoparticles that are anchored and encapsulated in a three-dimensional (3D) porous carbon framework (MnO@CF) have been constructed, which display nanosphere architecture with rich porosity, well-defined carbon framework configuration, and excellent structure stability. When evaluated as an anode material, the MnO@CF exhibits relatively high specific capacity of 939 mA h g(-1) at current rate of 0.2 A g(-1) over 200 cycles and excellent rate capability of 560.2 mA h g(-1) at 4 A g(-1). By virtue of its mechanical stability and desirable ionic/electronic conductivity, the specific design can be a promising approach to fabricate high-performance lithium-ion batteries.

Rational design of MnO/carbon nanopeapods with internal void space for high-rate and long-life li-ion batteries

Searching the long-life MnO-based materials for lithium ion batteries (LIBs) is still a great challenge because of the issue related to the volumetric expansion of MnO nanoparticles (NPs) or nanowires (NWs) during lithiation. Herein, we demonstrate an unexpected result that a peapod-like MnO/C heterostructure with internal void space can be facilely prepared by annealing the MnO precursor (MnO-P) NW/polydopamine core/shell nanostructure in an inert gas, which is very different from the preparation of typical MnO/C core/shell NWs through annealing MnO NW/C precursor nanostructure. Such peapod-like MnO/C heterostructure with internal void space is highly particular for high-performance LIBs, which can address all the issues related to MnO dissolution, conversion, aggregation and volumetric expansion during the Li(+) insertion/extraction. They are highly stable anode material for LIBs with a very high reversible capacity (as high as 1119 mAh g(-1) at even 500 mA g(-1)) and fast charge and discharge capability (463 mAh g(-1) at 5000 mA g(-1)), which is much better than MnO NWs (38 mAh g(-1) at 5000 mA g(-1)) and MnO/C core/shell NWs (289 mAh g(-1) at 5000 mA g(-1)). Such nanopeapods also show excellent rate capability (charged to 91.6% in 10.6 min using the constant current mode). Most importantly, we found that MnO/C nanopeapods show no capacity fading even after 1000 cycles at a high current density of 2000 mA g(-1), and no morphology change. The present MnO/C nanopeapods are the most efficient MnO-based anode materials ever reported for LIBs.

Peanut-like MnO@C core-shell composites as anode electrodes for high-performance lithium ion batteries

Peanut-like MnO@C core-shell composites with an internal carbon network (P-MnO@C) were prepared via an in situ synchronous graphitization and reduction process. These P-MnO@C composites exhibit high specific capacity and rate capability, good stability and excellent long-term cycling life for application in lithium ion batteries.

Novel MnO/conjugated microporous polymer derived-porous hard carbon nanocomposite for superior lithium storage

MnO/porous hard carbon nanocomposite as an anode material exhibits high discharge/charge capability and good cycling performance at 2 C for 300 cycles.

Recent advances in Mn-based oxides as anode materials for lithium ion batteries

The Mn-based oxides including MnO, Mn₃O₄, Mn₂O₃, MnO₂, CoMn₂O₄, ZnMn₂O₄and their carbonaceous composite/oxide supports with different morphologies and compositions as anode materials are reviewed.

Facile fabrication of Chinese lantern-like MnO@N–C: a high-performance anode material for lithium-ion batteries

Chinese lantern-like MnO@N–C is prepared via a facile process, and exhibits excellent electrochemical performance as an anode material for lithium-ion batteries.

Green and facile fabrication of hollow porous MnO/C microspheres from microalgaes for lithium-ion batteries

Hollow porous micro/nanostructures with high surface area and shell permeability have attracted tremendous attention. Particularly, the synthesis and structural tailoring of diverse hollow porous materials is regarded as a crucial step toward the realization of high-performance electrode materials, which has several advantages including a large contact area with electrolyte, a superior structural stability, and a short transport path for Li(+) ions. Meanwhile, owing to the inexpensive, abundant, environmentally benign, and renewable biological resources provided by nature, great efforts have been devoted to understand and practice the biotemplating technology, which has been considered as an effective strategy to achieve morphology-controllable materials with structural specialty, complexity, and related unique properties. Herein, we are inspired by the natural microalgae with its special features (easy availability, biological activity, and carbon sources) to develop a green and facile biotemplating method to fabricate monodisperse MnO/C microspheres for lithium-ion batteries. Due to the unique hollow porous structure in which MnO nanoparticles were tightly embedded into a porous carbon matrix and form a penetrative shell, MnO/C microspheres exhibited high reversible specific capacity of 700 mAh g(-1) at 0.1 A g(-1), excellent cycling stability with 94% capacity retention, and enhanced rate performance of 230 mAh g(-1) at 3 A g(-1). This green, sustainable, and economical strategy will extend the scope of biotemplating synthesis for exploring other functional materials in various structure-dependent applications such as catalysis, gas sensing, and energy storage.