ZnMn2O4/milk-derived Carbon hybrids with enhanced Lithium storage capability

One of the effective ways to improve the conductivity and structural stability of binary metal oxide nanostructures is to tightly composite them with nano-carbon materials with excellent conductivity. However, the introduction of low density carbon materials also reduces the energy density of batteries. Therefore, we provides a new idea to enhance the lithium storage performance of carbon/binary transition metal oxide anode materials by multi-element co-doping carbon. ZnMn₂O₄ provides high lithium storage capacity; non-metallic heteroatoms in milk-derived carbon greatly improve the conductivity of carbon materials; metal heteroatoms in milk-derived carbon increase the density of carbon materials. Multicomponent co-doping carbon can build up the mass specific capacity, ratio performance, cyclic life and mechanical properties of binary metal oxides/porous carbon nanocomposites. As the anode materials of lithium-ion batteries, the ZnMn₂O₄/MC (milk-derived carbon) hybrids deliver a high reversible capacity of 1352 mAh g⁻¹ after 400 cycles at 0.1 A g⁻¹, and a remarkable long-term cyclability with 635 mAh g⁻¹ after 300 cycles at 1.0 A g⁻¹.     

Nitrogen/sulfur co-doped disordered porous biocarbon as high performance anode materials of lithium/sodium ion batteries

Nitrogen/sulfur co-doped disordered porous biocarbon was facilely synthesized and applied as anode materials for lithium/sodium ion batteries. Benefiting from high nitrogen (3.38 wt%) and sulfur (9.75 wt%) doping, NS_1-1 as anode materials showed a high reversible capacity of 1010.4 mA h g⁻¹ at 0.1 A g⁻¹ in lithium ion batteries. In addition, it also exhibited excellent cycling stability, which can maintain at 412 mAh g^-1 after 1000 cycles at 5 A g⁻¹. As anode materials of sodium ion batteries, NS_1-1 can still reach 745.2 mA h g⁻¹ at 100 mAg^-1 after 100 cycles. At a high current density (5 A g^-1), the reversible capacity is 272.5 mA h g⁻¹ after 1000 cycles, which exhibits excellent electrochemical performance and cycle stability. The preeminent electrochemical performance can be attributed to three effects: (1) the high level of sulfur and nitrogen; (2) the synergic effect of dual-doping heteroatoms; (3) the large quantity of edge defects and abundant micropores and mesopores, providing extra Li/Na storage regions. This disordered porous biocarbon co-doped with nitrogen/sulfur exhibits unique features, which is very suitable for anode materials of lithium/sodium ion batteries.     

A novel flower-like metal-based oxides with cross-linked networks for rapid lithium-ion storage

A cross-linked MnO₂ coated ZnFe₂O₄ hollow nanosphere composite is synthesized and controlled via a facial and handy route. The connected MnO₂ nanoplates form a cross-linked network, which is conducive to the rapid transfer of Li ions. The composite with unique architecture can not only release the strain and stress caused by the insertion and desertion of lithium ions but also greatly improve the electrical conductivity and lithium ion diffusivity. Consequently, when used as a lithium-ion battery anode material, the electrode shows an excellent initial reversible capacity of 933.5 mAh/g with an initial coulombic efficiency of 62.5%. After 100 cycles, the reversible capacity stabilized at 605.6 mAh/g with a high capacity retention of 91% from the 20th cycle to the 100th cycle. At a high current density of 3 A/g, an excellent capacity of 390.6 mAh/g can be retained. In this case, the electrode shows broad application prospects for novel power storage systems.     

ZnSe/CoSe/NCDPH composites as anode materials for lithium ion batteries with high capacity and long cycle

In this paper, dopamine hydrochloride (DPH) is introduced to synthesize ZIF-8@ZIF-67@DPH in the preparation of ZIF-8@ZIF-67. ZnSe/CoSe/NC_DPH (N-doped carbon) composites are calcined in a high-temperature inert atmosphere with ZIF-8@ZIF-67@DPH as the precursor, selenium powder as the selenium source. ZnSe/CoSe/NC_DPH has high discharge specific capacity, good cycle stability and outstanding rate performance. The first discharge capacity of ZnSe/CoSe/NC_DPH is 1616.6 mAh g⁻¹ at the current density of 0.1 A g⁻¹, and the reversible capacity remains at 1214.2 mAh g⁻¹ after 100 cycles, the reversible capacity is 416.7 mAh g⁻¹ after 1000 cycles at 1 A g⁻¹. Therefore, ZnSe/CoSe/NC_DPH composites provide a new step for the research and synthesis of new stable, high-capacity, and safe high-performance lithium ion batteries. The bimetallic selenide composites not only have bimetallic active sites, but also can form synergistic effect between different metal phases, which can effectively reduce the capacity attenuation caused by volume expansion and reactive stress enrichment during lithium storage of metal oxide anode materials. Meanwhile, N-doped carbon can improve the conductivity and provide more active sites to store lithium, thus improving its lithium storage capacity.     

Composite materials of silver and natural graphite as anode with low sensibility to humidity

Sensitivity of anode materials to humidity is an important factor for the performance of lithium ion batteries. Here it is demonstrated for the first time that the sensitivity of composite anode materials of silver and natural graphite can be strikingly lowered. The composites are prepared by depositing silver ions onto the surface of natural graphite. After the following heat-treatment, silver ions turn into metallic silver and carbide Ag_xC by covering and/or removing active sites that absorb water very easily. Under high humidity condition (about 1000 ppm H₂O), the composite materials absorb strikingly less water resulting in still good electrochemical performance. In comparison, natural graphite without this treatment shows fast fade in capacity under high humidity even though it is good in cycling under low humidity (<100 ppm H₂O). Silver is a good matrix for lithium storage, and is assumed to contribute to reversible capacity since it enhances with the amount of deposited silver. This method can effectively lower the sensitivity of anode materials to humidity, and is promising in manufacturing lithium ion batteries under less critical conditions.     

Facile preparation of nanoporous TiO2/MoOx composite and its high lithium storage performances as an anode material

Nanoporous TiO₂/MoO_x composite is easily fabricated via one-step mild dealloying of well-designed TiMoAl ternary alloy in alkaline solution. Selectively leaching the Al atom from the precursor alloy resulted in the formation of nanoporous TiO₂/MoO_x composite accompanied with the natural oxidation of Ti and Mo atoms. The TiO₂/MoO_x composite is comprised of interconnected nanoscaled network backbone and hollow channels with the ligament size around 40 nm and the pore size around 90 nm. Owing to the rich porosity and the incorporation of MoO_x, the as-made nanocomposite exhibits markedly enhanced lithium storage performances with superior reversible capacity, outstanding rate capability, and prominent cycling stabilities compared with the pure TiO₂. Especially, the reversible capacity remains about 321.6 and 167.5 mA h g^?1 at the rate of 300 and 1000 mA g^?1, respectively, after long cycling up to 500 times. Benefitting from the unique performance and facile preparation, the TiO₂/MoO_x composite holds promising application potential as an anode material in lithium-ion batteries.     

MoO2 synthesized by reduction of MoO3 with ethanol vapor as an anode material with good rate capability for the lithium ion battery

MoO₂ synthesized through reduction of MoO₃ with ethanol vapor at 400 °C was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Its electrochemical performance as an anode material for lithium ion battery was tested by cyclic voltammetry (CV) and capacity measurements. During the reduction process, the starting material (MoO₃) collapsed into nanoparticles (∼100 nm), on the nanoparticles remains a carbon layer from ethanol decomposition. Rate capacity and cycling performance of the as-prepared product is very satisfactory. It displays 318 mAh g⁻¹ in the initial charge process with capacity retention of 100% after 20 cycles in the range of 0.01–3.00 V vs. lithium metal at a current density of 5.0 mA cm⁻², and around 85% of the retrievable capacity is in the range of 1.00–2.00 V. This suggests the application of this type of MoO₂ as anode material in lithium ion batteries.     

Magnetic tubular carbon nanofibers as anode electrodes for high‐performance lithium‐ion batteries

Novel magnetic tubular carbon nanofibers (MTCFs) are prepared through the combination technique of hypercrosslinking, control extraction, and carbonization. The diameter of MTCFs is mainly concentrated between 90 and 120 nm, and the average tube diameter is about 30 nm. A trace amount of Fe₃O₄ exists inside the MTCFs with a particle size of 3 nm, which is formed by in situ conversion of the catalyst (FeCl₃) for the hypercrosslinking reaction. The MTCFs with high surface area (448.74 m² g^?1) and porous wall are used as anode material for lithium‐ion batteries. The electrochemical properties of MTCFs are compared, and tubular carbon nanofibers (TCFs) prepared by the complete extraction. Electrochemical analysis shows that the introduction of Fe₃O₄ nanoparticles makes MTCFs have higher reversible capacity and better rate performance. MTCFs exhibit high reversible specific capacity of 1011.7 mAh g^?1 after 150 cycles at current density of 100 mA g^?1. Even at high current density of 3000 mA g^?1, a remarkable reversible capacity of 270.0 mAh g^?1 is still delivered. Thus, the novel MTCFs show potential application value in anode material for high‐performance lithium‐ion battery.     

Electrochemical performance of Mn3O4 nanorods by N-doped reduced graphene oxide using ultrasonic spray pyrolysis for lithium storage

The crumpled N-doped reduced graphene oxide wrapped Mn₃O₄ nanorods (Mn-NrGO) composite are synthesized via a combination of spray pyrolysis and a hydrothermal process for lithium ion batteries. The Mn₃O₄ nanorods are uniformly dispersed in the conductive matrix of crumpled N-doped reduced graphene oxide, forming a uniform wrapped composite and stopping them from restacking, which synergistically enhanced the Li⁺ ion conductivity. The well-defined Mn₃O₄ nanorods, strong interaction between Mn₃O₄ and NrGO, and highly graphitic properties of Mn-NrGO result in superior reversible capacity, long cycle life, and superior rate performance of approximately 1500 mAh/g at 0.1 C after 100 cycles and >660S mAh/g at 1.0 C after 500 cycles.     

Energy storage of thermally reduced graphene oxide

The energy-storage capacity of reduced graphene oxide (rGO) is investigated in this study. The rGO used here was prepared by thermal annealing under a nitrogen atmosphere at various temperatures (300, 400, 500 and 600 °C). We measured high-pressure H₂ isotherms at 77 K and the electrochemical performance of four rGO samples as anode materials in Li-ion batteries (LIBs). A maximum H₂ storage capacity of ∼5.0 wt% and a reversible charge/discharge capacity of 1220 mAh/g at a current density of 30 mA/g were achieved with rGO annealed at 400 °C with a pore size of approximately 6.7 Å. Thus, an optimal pore size exists for hydrogen and lithium storage, which is similar to the optimum interlayer distance (6.5 Å) of graphene oxide for hydrogen storage applications.     

Hierarchical novel NiCo2O4/BiVO4 hybrid heterostructure as an advanced anode material for rechargeable lithium ion battery

Hybrid metal oxide heterostructures have been considered as ideal and potential anode materials for lithium ion batteries (LIBs) due to their better electrochemical performances, such as reversible capacity, structural stability and electronic conductivity. Herein, we have demonstrated synthesis of NiCo₂O₄/BiVO₄ heterostructures by simple hydrothermal strategy to construct hybrid xNiCo₂O₄/(1–x)BiVO₄ heterostructures with four selected compositions, that is, x = 10%, 20%, 30% and 40%. XRD shows the phases of NiCo₂O₄ and BiVO₄ and FE-SEM data revealed strong interface coupling between NiCo₂O₄ nanowires and BiVO₄ dendrites. Upon testing for electrochemical properties, the optimized composition of 30%NiCo₂O₄-70% BiVO₄ showed higher reversible capacity of 408.6 mAh/g at a constant current rate of 0.5 A/g after 1000 cycles with columbic efficiency around 99% suggesting potential electrode material for high-performance LIBs. The higher capacity is mainly attributed to the large surface area which can provide more channels and locations for fast Li ion intercalation/de-intercalation into electrode materials. Additionally, improved Li ion storage capacity with superior rate capability of BN-30 electrode could be attributed to its lower charge-transfer resistance. The dendritic and nanowire heterostructure novel system with good stable capacity for LIBs is hitherto unattempted.     

Anodic behavior of zinc in Zn-MnO2 battery using ERDA technique

The commercial, alkaline zinc-manganese dioxide (Zn-MnO₂) primary battery has been transformed into a secondary battery using lithium hydroxide electrolyte. Galvanostatic discharge–charge experiments showed that the capacity decline of the Zn-MnO₂ battery is not caused by the MnO₂ cathode, but by the zinc anode. The electrochemical data indicated that a rechargeable battery made of porous zinc anode can have a larger discharge capacity of 220 mAh/g than a planar zinc anode of 130 mAh/g. The cycling performance of these two anodes is demonstrated. Structural and depth profile analyses of the discharged anodes are examined by X-ray diffraction (XRD) and elastic recoil detection analysis (ERDA) techniques.     

Superior catalytic effect of titania - porous carbon composite for the storage of hydrogen in MgH2 and lithium in a Li ion battery

A novel nanocomposite (0.2TiO₂ + AC) with two promising applications is demonstrated, (i) as an additive for promoting hydrogen storage in magnesium hydride, (ii) as an active electrode material for hosting lithium in Li ion batteries (surface area of activated carbon (AC): 491 m²/g, pore volume: 0.252 cc/g, size of TiO₂ particles: 20–30 nm). Transmission electron microscopy study provides evidence that well dispersed TiO₂ nanoparticles are enclosed by amorphous carbon nets. A thermogravimetry-differential scanning calorimetry (TG-DSC) study proves that the nanocomposite is thermally stable up to ∼400 °C. Volumetric hydrogen storage tests and DSC studies further prove that a 3 wt% of 0.2TiO₂+AC nanocomposite as additive not only lowers the dehydrogenation temperature of MgH₂ over 100 °C but also maintains the performance consistency. Moreover, as a working electrode for Li ion battery, 0.2TiO₂+AC offers a reversible capacity of 400 mAh/g at the charge/discharge rate of 0.1C and consistent stability up to 43 cycles with the capacity retention of 160 mAh/g at 0.4C. Such cost effective-high performance materials with applications in two promising areas of energy storage are highly desired for progressing towards sustainable energy development.     

New strategy to prepare nitrogen self-doped graphene nanosheets by magnesiothermic reduction and its application in lithium ion batteries

Nitrogen self-doped graphene (N/G) nanosheets were prepared through magnesiothermic reduction of melamine. The obtained N/G features porous structure consisting of multi-layer nanosheets. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectra and X-ray diffraction (XRD). As anode of lithium ion batteries (LIBs), it exhibits excellent reversible specific capacity of 1753 mAh g⁻¹ at 0.1 A g^-1 after 200 cycles. The reversible capacity can maintain at 1322 mAh g⁻¹ after 500 cycles at 2 A g⁻¹. At the same time, all results indicate remarkable cycle stability and rate performance as anode materials. Furthermore, this study demonstrates an economical, clean and facile strategy to synthesize N/G nanosheets from cheap chemicals with excellent electrochemical performance in LIBs.     

Niobium carbide/reduced graphene oxide hybrid porous aerogel as high capacity and long‐life anode material for Li‐ion batteries

Two‐dimensional material MXenes owing to their hydrophilic nature, surface termination, and high conductivity can be used in the energy storage device as an anode material. However, poor ion transfer and less available intercalating sites due to self‐stacking of MXene sheets prevent comprehensive utilization of their electrochemical properties. To resolve this problem, a facile method is introduced in this paper to disperse MXene sheets onto reduced graphene oxide sheets to form a porous structure by enhancing electrostatic interactions between two components, which can facilitate ion movement and provide access of ions to more intercalating sites. This hybrid material delivered a capacity of 357 mAh g^?1 at 0.05 A g^?1 as anode in case of lithium‐ion batteries. Furthermore, the hybrid material showed exceptional stability even after 1000 cycles at 1 A g^?1. Current work offers an easy approach for the synthesis of high‐performance niobium carbide‐based hybrid energy storage materials.     

Anatase/rutile-TiO2 hollow hierarchical architecture modified by SnO2 toward efficient lithium storage

Hierarchical architecture of anatase/rutile-mixed phases TiO₂ with hollow interior was successfully fabricated via a Topotactic synthetic method, including the synthesis of CaTiO₃ precursors and transforming them into TiO₂ through ion-exchange process. The as-synthesized TiO₂ hierarchical architectures as the anode materials were used as lithium-ion batteries (LIBs). Compared with TiO₂ samples, the TiO₂@SnO₂-5% shows the improved lithium storage capacity, cycling performance and rate properties. The impedance of the TiO₂ electrode decreases evidently after adding few amount of SnO₂. The hollow hierarchical structure with different compositions provide much more active sites, and well connect interface among anatase, rutile, and SnO₂, facilitating the electron and ion transport quickly and efficiently. Addition appropriate number of SnO₂ not only well kept the hierarchical architecture but also enhanced the capacity and conductivity of the TiO₂ sample. As a result, TiO₂@SnO₂-5% exhibited excellent lithium storage performance.     

Molybdenum carbide nanocrystals modified carbon nanofibers as electrocatalyst for enhancing polysulfides redox reactions in lithium-sulfur batteries

The high performance of lithium sulfur (Li S) batteries is the focus of research in recent years. However, the low sulfur loading, shuttling effect in electrolyte, and poor cycling stability limit their applications. Herein, molybdenum carbide nanocrystals embedded carbon nanofibers (Mo₂C@CFs: MCCFs) hybrid membrane was prepared in situ on CFs membrane based on carbonthermal reduction of ammonium molybdate. The fibrous MCCFs network is used as the current collector with Li₂S₆ catholyte solution for Li S batteries, which inhibits the shuttle effect and accelerates kinetics redox reaction. In addition, Mo₂C, as electrocatalyst, promotes nucleation of Li₂S of the MCCFs substance, which can reduce polarization and increase the specific capacity. As a result, the free-standing MCCFs@Li₂S₆ electrode (sulfur loading: 4.74 mg) shows a capacity of 977 mAh g⁻¹ and maintains at 828 mAh g⁻¹ at 0.2 C over 250 cycles, and indicates excellent reversibility and cycling stability. Even with sulfur loading as high as 7.11 mg, the MCCF@Li₂S₆ electrode exhibits an extremely high capacity of 5.75 mAh. Meanwhile, the Mo₂C modified CFs can be effectively retarding the self-discharge behavior by trapping the polysulfides. Furthermore, the stability improvement of lithium anode state by effectively suppressing the shuttle effect of polysulfide, played an important role in enhancing the electrochemical performance.     

Carbon particles modified macroporous Si/Ni composite as an advanced anode material for lithium ion batteries

Carbon particles modified macroporous Si/Ni composite (MP-Si/Ni/C) is easily obtained via a facile fabrication of porous Si/Ni precursor by dealloying SiNiAl alloy followed by a surface growth of carbon nanoparticles. MP-Si/Ni/C composite possesses the multiply conductivity modification that are built through mixing Ni dispersoid and growing one layer of carbon particles. Coupled with the structural advantages of interconnected network backbone, rich voids, and the coated carbon particles, MP-Si/Ni/C exhibits dramatically enhanced lithium storage performances with excellent reversible capacity, enhanced rate performance, as well as outstanding cycling stability compared with pure MP-Si and MP-Si/Ni. Especially, the reversible capacity remains up to 1113.1 and 708.8 mA h g⁻¹ at the current densities of 200 and 1000 mA g⁻¹ after 120 cycles, respectively. Besides, it shows excellent rate capability even when continuously cycled at high current density of 3000 mA g⁻¹. With the advantages of unique structure, excellent performances, and facile preparation, the as-made MP-Si/Ni/C composite shows promising application potential as an alternative anode for lithium ion batteries.     

Gamma-ray radiation on P-doped Si nanoparticles towards the Li+-storage performances

The high theoretical capacity of Si makes it a promising anode material for lithium ion batteries. However, the poor electrical conductivity and large volume expansion during lithiation/delithiation hinders its electrochemical performances. Herein, we report a γ irradiation treatment method to prepare P-doped Si nanoparticles. The sample exhibits a capacity of 1698 mAh/g at 0.1 C rate after 100 cycles, which is about 3 times larger than that of undoped Si. The rate performance of γ irradiated P-doped Si is also highly improved when compared to P-doped Si without γ irradiation treatment. The enhanced performance can be attributed that γ irradiation can facilitate the phosphorus doping into Si lattice, which can enhance the electrical conductivity of Si.     

Well-dispersed Sb2O3 nanoparticles encapsulated in multi-channel-carbon nanofibers as high-performance anode materials for Li/dual-ion batteries

Reasonable design and construction of electrode materials with high-performance and low-cost are essential for Li-ion batteries (LIBs) and dual-ion batteries (DIBs). Herein, an eco-friendly and facile strategy is proposed to encapsulate Sb₂O₃ nanoparticles in one-dimensional (1D) multi-nanochannel-containing carbon nanofibers (Sb₂O₃@MCNF) using the electrospinning method as well as the subsequent calcination. Such unique construction not only effectively reduces the large volume variation during cycling, but also achieves the fast Li⁺/e^? transportation. As a result, the optimized sample with the precursor triphenylantimony (III) content of 0.35 g (Sb₂O₃@MCNF-0.35) exhibits superior electrochemical performance as anode materials for LIBs and Li-based DIBs (LDIBs), including high reversible capacity (~333.5 mAh g^?1 at 1 A g^?1 for LIBs and 233.5 mAh g^?1 at 0.2 A g^?1 for LDIBs) and favorable cycling stability (over 800 cycles for LIBs and 100 cycles for LDIBs). These results demonstrate that the well-designed Sb₂O₃@MCNF-0.35 can availably boost the electrochemical performance, which provides vast potential for applications in the field of high-performance energy storage equipment.