Facile Construction of Porous ZnMn2O4 Hollow Micro-Rods as Advanced Anode Material for Lithium Ion Batteries

Spinel ZnMn₂O₄ is considered a promising anode material for high-capacity Li-ion batteries due to their higher theoretical capacity than commercial graphite anode. However, the insufficient cycling and rate properties seriously limit its practical application. In this work, porous ZnMn₂O₄ hollow micro-rods (ZMO HMRs) are synthesized by a facile co-precipitation method coupled with annealing treatment. On the basis of electrochemical analyses, the as-obtained samples are first characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and scanning electron microscopy techniques. The influences of different polyethylene glycol 400 (PEG 400) additions on the formation of the hollow rod structure are also discussed. The abundant multi-level pore structure and hollow feature of ZMO HMRs effectively alleviate the volume expansion issue, rendering abundant electroactive sites and thereby guaranteeing convenient Li⁺ diffusion. Thanks to these striking merits, the ZMO HMRs anode exhibits excellent electrochemical lithium storage performance with a reversible specific capacity of 761 mAh g^-1 at a current density of 0.1 A g^-1, and a long-cycle specific capacity of 529 mAh g^-1 after 1000 cycles at 2.0 A g^-1 and keep a remarkable rate capability. In addition, the assembled ZMO HMRs-based full cells deliver an excellent rate capacity, and when the current density returns to 0.05 A g^-1, the specific capacity can still reach 105 mAh g^-1 and remains at 101 mAh g^-1 after 70 cycles, maintaining a material-level energy density of approximately 273 Wh kg^-1. More significantly, such striking electrochemical performance highlights that porous ZMO HMRs could be a promising anode candidate material for LIBs.

Morphological and Electrochemical Properties of ZnMn2O4 Nanopowders and Their Aggregated Microspheres Prepared by Simple Spray Drying Process

Phase-pure ZnMn₂O₄ nanopowders and their aggregated microsphere powders for use as anode material in lithium-ion batteries were obtained by a simple spray drying process using zinc and manganese salts as precursors, followed by citric acid post-annealing at different temperatures. X-ray diffraction (XRD) analysis indicated that phase-pure ZnMn₂O₄ powders were obtained even at a low post-annealing temperature of 400 °C. The post-annealed powders were transformed into nanopowders by simple milling process, using agate mortar. The mean particle sizes of the ZnMn₂O₄ powders post-treated at 600 and 800 °C were found to be 43 and 85 nm, respectively, as determined by TEM observation. To provide practical utilization, the nanopowders were transformed into aggregated microspheres consisting of ZnMn₂O₄ nanoparticles by a second spray drying process. Based on the systematic analysis, the optimum post-annealing temperature required to obtain ZnMn₂O₄ nanopowders with high capacity and good cycle performance was found to be 800 °C. Moreover, aggregated ZnMn₂O₄ microsphere showed improved cycle stability. The discharge capacities of the aggregated microsphere consisting of ZnMn₂O₄ nanoparticles post-treated at 800 °C were 1235, 821, and 687 mA h g⁻¹ for the 1st, 2nd, and 100th cycles at a high current density of 2.0 A g⁻¹, respectively. The capacity retention measured after the second cycle was 84%.

Magnetized manganese-doped watermelon rind biochar as a novel low-cost catalyst for improving oxygen reduction reaction in microbial fuel cells

Microbial fuel cells (MFCs) are promising equipment for water treatment and power generation. The catalyst used in the oxygen reduction reaction (ORR) at the cathode is a critical factor for efficacy of MFCs. Therefore, it is important to develop cost-effective cathode catalysts to enhance application of MFCs. In the current study, a novel cathode catalyst was developed, which was annealed with watermelon rind as raw material and transition metals including iron, and manganese were introduced. The 700Mn/Fe@WRC catalyst, which was annealed at 700 °C, exhibited excellent electrochemical performance. The high relative content of pyridine nitrogen caused by the inherent nitrogen element of the watermelon rind and the high content of iron and manganese elements introduced resulted in increase in electrochemical surface area to 657.6 m²/g. The number of electrons transferred ORR was 3.96, indicating that ORR occurs through a four-electron pathway. The maximum power density of MFCs was 399.3 ± 7.4 mW/m² with a fitting total internal resistance of 15.242 Ω, and the removal efficiency of COD was 97.1 ± 1.2%. The cost of the 700Mn/Fe@WRC catalyst was approximately 0.15 $/g, which is significantly lower compared with Pt/C (33.0 $/g). Experimental verification showed that the 700Mn/Fe@WRC prepared using the economical watermelon rind biochar (WRC) is an excellent substitute for non-precious metal catalysts used in MFCs.

Energy efficient electrodes for lithium-ion batteries: Recovered and processed from spent primary batteries

In an attempt to develop low cost, energy efficient and advanced electrode material for lithium-ion batteries (LIBs), waste-to-wealth derived as well as value added spent battery materials as potential alternatives assume paramount importance. By combining the low lithiation potential advantages, one can arrive at energy efficient electrodes bestowed with cost effective and eco-friendly benefits required for practical LIB applications. In the present study, Zn and Mn-salts along with C were successfully extracted from the spent zinc carbon batteries through a simple and efficient hydrometallurgy approach and decomposed thermally to obtain ZnMn₂O₄ at 350 °C for 12 h and 450 °C for 3 h. Further, C-ZnMn₂O₄ nanocomposites were prepared and demonstrated for appreciable electrochemical performance in LIB assembly. Our results show that C-ZnMn₂O₄ composites prepared at 350 °C and 450 °C demonstrate better performance than pristine ZnMn₂O₄ anode due to the improved electronic conductivity rendered by the added carbon obtained from spent primary battery. In particular, C-ZnMn₂O₄ at 350 °C @12 h exhibits appreciable electrochemical performance by showing a stable and higher capacity of 600 mAhg^-1 at a current density of 50 mAg^-1 in the voltage range of 0.01-3.0 V and qualifies it as a better performing cost-effective anode for LIBs.

Influence of phase variation of ZnMn2O4/carbon electrodes on cycling performances of Li-ion batteries

Due to the high specific capacity and low cost, transition metal oxides (TMOs) exhibit huge potential as anode materials for high-performance Li-ion batteries.

Room-temperature solution synthesis of ZnMn2O4 nanoparticles for advanced electrochemical lithium storage

Taking advantage of synergistic effects, the ternary metal oxides have attracted tremendous interest. Herein, ZnMn₂O₄ nano-particles have been fabricated via a facile one-step approach at room temperature, that of simply mixing ZnO and MnO in KOH aqueous solution without templates. When used as an anode for lithium ion batteries, it delivers the excellent structure stability (1028.9 mA h g⁻¹ at 1.0 A g⁻¹ after 400 cycles). Surprisingly, the low-cost and eco-friendly route provides a novel strategy to synthesize the mixed transition metal oxide electrodes with readily scaled-up production.

ZnMn₂O₄ nanoparticles were fabricated via a low-cost and ecofriendly one-step approach at room temperature. The particles exhibited excellent structure stability and superior lithium storage.

Mesoporous ZnMn2O4 Microtubules Derived from a Biomorphic Strategy for High-Performance Lithium/Sodium Ion Batteries

ZnMn₂O₄ microtubules (ZMO-MTs) with a mesoporous structure are fabricated by a novel yet effective biomorphic approach employing cotton fiber as a biotemplate. The fabricated ZMO-MT has approximately an inner diameter of 8.5 μm and wall thickness of 1.5 μm. Further, the sample of ZMO-MT displays a large specific surface area of 48.5 m² g^-1. When evaluated as a negative material for Li-ion batteries, ZMO-MT demonstrates an improved cyclic performance with discharge capacities of 750.4 and 535.2 mA h g^-1 after 300 cycles, under current densities of 200 and 500 mA g^-1, respectively. Meanwhile, ZMO-MT exhibits superior rate performances with high reversible discharge capacities of 614.7 and 465.2 mA h g^-1 under high rates of 1000 and 2000 mA g^-1, respectively. In sodium ion batteries applications, ZMO-MT delivers excellent high discharge capacities of 102 and 71.4 mA h g^-1 after 300 cycles under 100 and 200 mA g^-1, respectively. An excellent rate capability of 58.2 mA h g^-1 under the current density of 2000 mA g^-1 can also be achieved. The promising cycling performance and rate capability could be benefited from the unique one-dimensional mesoporous microtubular architecture of ZMO-MT, which offers a large electrolyte/electrode accessible contact area and short diffusion distance for both of ions and electrons, buffering the volume variation originated from the repeated ion intercalation/deintercalation processes.

MnWO4 nanoparticles as advanced anodes for lithium-ion batteries: F-doped enhanced lithiation/delithiation reversibility and Li-storage properties

F-Doped MnWO4 nano-particles were synthesized by a one-pot hydrothermal reaction. When evaluated as an electrode material for a Li ion battery, the F-doped nano-MnWO4 delivers a theoretical capacity of 708 mA h g-1 and a long cycle life, as demonstrated by more than 85% capacity retention when cycled for 150 cycles.

Role of manganese dioxide in the recovery of oxide-sulphide zinc ore

In this article, the role of MnO₂ in the recovery of oxide-sulphide zinc ore discussed. Through adopting various modern analysis techniques (such as X-ray diffraction pattern, X-ray photoelectron spectroscopy, scanning electron microscope, energy dispersive X-ray analysis, and fourier transform infrared spectroscopy), the function and mechanism of MnO₂ during the phase transformation process is found out. Thermodynamic mechanisms involved in the phase transformation process with or without addition of manganese dioxide investigated by exploiting the Equilib module of FactSage. What's more, XRD patterns, XPS spectra and SEM-EDAX analyses of zinc calcines verify well the calculations of FactSage. Results reveal that the addition of MnO₂ will produce an aggregation of ZnMn₂O₄, a valuable energy material, while roasting on its own, results in generating undesirable Zn₂SiO₄, the oxidation degree being relatively low. Moreover, XRD pattern of zinc calcine and FT-IR spectrum of yellow product collected in the calcination process prove that the sulphur-fixing value of the additive MnO₂, which can promote transforming to the elemental sulphur. The volatile S can be collected through a simple guiding device. In this process, the emission of SO₂ effectively avoids, thus MnO₂ deems as a potential additive in the recovery of oxide-sulphide zinc ore.

Delicate Control of Multishelled Zn-Mn-O Hollow Microspheres as a High-Performance Anode for Lithium-Ion Batteries

Mixed/composite oxides of transition metals with hollow structures, especially multishelled hollow architecture, have promising potential for different applications, but their syntheses still remain a big challenge. Herein, a facile coordination polymer precursor method was developed to construct various multishelled Zn-Mn-O hollow microspheres, including ZnMnO₃, ZnMn₂O₄, and ZnMn₂O₄/Mn₂O₃. The composition of the hollow structures can be adjusted by controlling the composition of the coordination polymer precursors, which are easily obtained with Zn²⁺, Mn²⁺, and salicylic acid under solvothermal conditions. With a simple programmable heating process, the shell of the hollow structures can be adjusted and double-/triple-shelled ZnMnO₃, ZnMn₂O₄, and ZnMn₂O₄/Mn₂O₃ hollow microspheres have been controllably obtained. When the triple-shelled ZnMn₂O₄ hollow microspheres are used as anode materials for lithium-ion batteries, excellent activity and enhanced stability can be achieved. The triple-shelled hollow ZnMn₂O₄ exhibits a reversible capacity of 537 mA·h·g^-1 at 400 mA·g^-1 and a nearly 100% capacity retention after 150 cycles. This strategy is facile and scalable for the production of high-quality complex hollow nanostructures, with the possibility of extension to the preparation of other mixed metal oxides with complex structures.

Fabrication of CoTiO3-TiO2 composite films from a heterobimetallic single source precursor for electrochemical sensing of dopamine

Cobalt titanate-titania composite oxide films have been grown on FTO-coated glass substrates using a single-source heterometallic complex [Co2Ti4(μ-O)6(TFA)8(THF)6]·THF () which was obtained in quantitative yield from the reaction of diacetatocobalt(ii) tetrahydrate, tetraisopropoxytitanium(iv), and trifluoroacetic acid from a tetrahydrofuran solution. Physicochemical investigations of complex have been carried out by melting point, FT-IR, thermogravimetric and single-crystal X-ray diffraction analyses. CoTiO3-TiO2 films composed of spherical objects of various sizes have been grown from by aerosol-assisted chemical vapor deposition at different temperatures of 500, 550 and 600 °C. Thin films characterized by XRD, Raman and X-ray photoelectron spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis have been explored for electrochemical detection of dopamine (DA). The cyclic voltammetry with the CoTiO3-TiO2 electrode showed a DA oxidation peak at +0.215 V while linear sweep voltammetry displayed a detection limit (LoD) of 0.083 μM and a linear concentration range of 20-300 μM for DA. Thus, the CoTiO3-TiO2 electrode is a potential candidate for the sensitive and selective detection of DA.

A new approach to improve the electrochemical performance of ZnMn2O4 through a charge compensation mechanism using the substitution of Al3+ for Zn2+

ZnMn₂O₄ and Zn_1−xAl_xMn₂O₄ were synthesized by a spray drying process followed by an annealing treatment. Their structural and electrochemical characteristics were investigated by SEM, XRD, XPS, charge–discharge tests and EIS. XPS data indicate that the substitution of Al³⁺ for Zn²⁺ causes manganese to be in a mixed valence state by a charge compensation mechanism. Moreover, the presence of this charge compensation significantly improves the electrochemical performance of Zn_1−xAl_xMn₂O₄, such as increasing the initial coulombic efficiency, stabilizing the cycleability as well as improving the rate capability. The sample with 2% Al doping shows the best performance, with a first cycle coulombic efficiency of 69.6% and a reversible capacity of 597.7 mA h g⁻¹ after 100 cycles. Even at the high current density of 1600 mA g⁻¹, it still retained a capacity of 558 mA h g⁻¹.

This work reports the nonequivalent substitution of ZnMn₂O₄. This is a new approach to improve the electrochemical performance of ZnMn₂O₄ through a charge compensation mechanism using the substitution of Al³⁺ for Zn²⁺.

Hierarchical porous ZnMnO3 yolk–shell microspheres with superior lithium storage properties enabled by a unique one-step conversion mechanism

ZnMnO₃ has attracted enormous attention as a novel anode material for rechargeable lithium-ion batteries due to its high theoretical capacity. However, it suffers from capacity fading because of the large volumetric change during cycling. Here, porous ZnMnO₃ yolk–shell microspheres are developed through a facile and scalable synthesis approach. This ZnMnO₃ can effectively accommodate the large volume change upon cycling, leading to an excellent cycling stability. When applying this ZnMnO₃ as the anode in lithium-ion batteries, it shows a remarkable reversible capacity (400 mA h g⁻¹ at a current density of 400 mA g⁻¹ and 200 mA h g⁻¹ at 6400 mA g⁻¹) and excellent cycling performance (540 mA h g⁻¹ after 300 cycles at 400 mA g⁻¹) due to its unique structure. Furthermore, a novel conversion reaction mechanism of the ZnMnO₃ is revealed: ZnMnO₃ is first converted into intermediate phases of ZnO and MnO, after which MnO is further reduced to metallic Mn while ZnO remains stable, avoiding the serious pulverization of the electrode brought about by lithiation of ZnO.

ZnMnO₃ has attracted enormous attention as a novel anode material for rechargeable lithium-ion batteries due to its high theoretical capacity.

Graphene-oxide-wrapped ZnMn2O4 as a high performance lithium-ion battery anode

Cation distribution between tetrahedral and octahedral sites within the ZnMn₂O₄ spinel lattice, along with microstructural features, is affected greatly by the temperature of heat treatment. Inversion parameters can easily be tuned, from 5%-19%, depending on the annealing temperature. The upper limit of inversion is found for T = 400 °C as confirmed by x-ray powder diffraction and Raman spectroscopy. Excellent battery behavior is found for samples annealed at lower temperatures; after 500 cycles the specific capacity for as-prepared ZnMn₂O₄ is 909 mAh g^-1, while ZnMn₂O₄ heat-treated at 300 °C is 1179 mAh g^-1, which amounts to 101% of its initial capacity. Despite the excellent performance of a sample processed at 300 °C at lower charge/discharge rates (100 mAh g^-1), a drop in the specific capacity is observed with rate increase. This issue is solved by graphene-oxide wrapping: the specific capacity obtained after the 400th cycle for graphene-oxide-wrapped ZnMn₂O₄ heat-treated at 300 °C is 799 mAh g^-1 at a charge/discharge rate 0.5 A g^-1, which is higher by a factor of 6 compared to samples without graphene -oxide wrapping.

Template-free fabrication of graphene-wrapped mesoporous ZnMn2O4 nanorings as anode materials for lithium-ion batteries

We rationally designed a facile two-step approach to synthesize ZnMn₂O₄@G composite anode material for lithium-ion batteries (LIBs), involving a template-free fabrication of ZnMn₂O₄ nanorings and subsequent coating of graphene sheets. Notably, it is the first time that ring-like ZnMn₂O₄ nanostructure is reported. Moreover, our system has been demonstrated to be quite powerful in producing ZnMn₂O₄ nanorings regardless of the types of Zn and Mn-containing metal salts reactants. The well-known inside-out Ostwald ripening process is tentatively proposed to clarify the formation mechanism of the hollow nanorings. When evaluated as anode material for LIBs, the resulting ZnMn₂O₄@G hybrid displays significantly improved lithium-storage performance with high specific capacity, good rate capability, and excellent cyclability. After 500 cycles, the ZnMn₂O₄@G hybrid can still deliver a reversible capacity of 958 mAh g^-1 at a current density of 200 mA g^-1, much higher than the theoretical capacity of 784 mAh g^-1 for pure ZnMn₂O₄. The outstanding electrochemical performance should be reasonably ascribed to the synergistic interaction between hollow and porous ZnMn₂O₄ nanorings and the three-dimensional interconnected graphene sheets.

Nano-particle assembled porous core-shell ZnMn2O4 microspheres with superb performance for lithium batteries

Porous ZnMn₂O₄ microspheres were prepared via a facile co-precipitation method followed by calcination at various temperatures and evaluated as anode materials for lithium ion batteries. The sample prepared at 600 °C outperformed the other samples in terms of electrochemical performance with high reversible capacity, high-rate capability, and excellent cycling performance. The capacity of the sample remained as high as 999 mAh g^-1 at a current rate of 100 mA g^-1 after 50 cycles-one of the best ever reported for ZnMn₂O₄-based materials. A high reversible capacity of 400 mAh g^-1 was retainable at a current density of 2000 mA g^-1 after 2500 cycles. A novel electrochemical reaction mechanism of ZnMn₂O₄ anodes was established and investigated at length. The Mn₃O₄ observed during the charge process was largely responsible for the enhanced performance, as confirmed by x-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The relatively large surface area, abundant porosity, large ion exchange space, and strong mechanical stability of the porous connected 3D framework were responsible for the unique oxidation/reduction Mn²⁺ ↔ Mn³⁺ process we observed.

Hierarchical porous ZnMn2O4microspheres assembled by nanosheets for high performance anodes of lithium ion batteries

Hierarchical porous ZnMn₂O₄microspheres assembled by nanosheets are fabricated and they exhibit outstanding electrochemical performance for lithium-ion battery anodes.

Self-sacrificial template formation of ultrathin single-crystalline ZnMn2O4 nanoplates with enhanced Li-storage behaviors for Li-ion batteries

Ultrathin single-crystalline ZnMn₂O₄ nanoplates were first designed and tailored as an anode for advanced Li-ion batteries via an efficient self-sacrificial template synthetic strategy, and delivered excellent Li-storage performance at high C rates.

An overview of AB2O4- and A2BO4-structured negative electrodes for advanced Li-ion batteries

Energy-storage devices are state-of-the-art devices with many potential technical and domestic applications.

Hierarchical Porous ZnMn2 O4 Hollow Nanotubes with Enhanced Lithium Storage toward Lithium-Ion Batteries

We have purposefully developed a smart template-engaged methodology to efficiently fabricate well-defined ternary spinel ZnMn2 O4 hollow nanotubes (NTs). The procedure involves coating carbon nanotubes (CNTs) with ZnMn2 O4 nanosheets (NSs), followed by heating at high temperature in air to oxidize the CNT template. Physicochemical characterization demonstrated that the formed ZnMn2 O4 NTs with a diameter of approximately 100 nm were composed of assembled NSs and/or nanoparticles (NPs) as building blocks and possessed numerous nanopores of several nanometers in the sidewall of the NTs. In favor of the intrinsic structural advantages, the resulting ZnMn2 O4 NTs exhibited superior electrochemical lithium-storage performance with a large capacity, good rate behavior, and excellent cyclability when evaluated as promising anodes for lithium-ion batteries (LIBs). The remarkable electrochemical performance was rationally ascribed to the appealing one-dimensional (1D) porous hollow tubular architecture with nanoscale subunits and mesopores in the sidewalls, which decreased the diffusion length for the Li(+) ions, improved the kinetic process, and enhanced the structural integrity with sufficient void space to tolerate the volume variation during Li(+) -ion insertion/extraction. These results highlight the promising application of 1D ZnMn2 O4 NTs as anodes for high-performance LIBs.

Heterostructured core-shell ZnMn₂O₄ nanosheets@carbon nanotubes' coaxial nanocables: a competitive anode towards high-performance Li-ion batteries

In this study, we rationally designed a rapid, low-temperature yet general synthetic methodology for the first time, involving in situ growth of two-dimensional (2D) birnessite-type MnO2 nanosheets (NSs) upon each carbon nanotube (CNT), and we designed the subsequent phase transformation into untrathin mesoporous ZnMn2O4 NSs with a thickness of ∼2-3 nm at room temperature to efficiently fabricate heterostructured core-shell ZnMn2O4 NSs@CNT coaxial nanocables with well-dispersed and tunable ZnMn2O4 loading. The underlying insights into the low-temperature formation mechanism of the unique core-shell hybrid nanoarchitectures were tentatively proposed here. When utilized as a high-performance anode for advanced LIBs, the resultant core-shell ZnMn2O4@CNTs' coaxial nanocables (∼84.5 wt.% loading) exhibited large specific discharge capacity (∼1033 mAh g(-1)), good rate capability (∼528 mAh g(-1)) and excellent cycling stability (average capacity degradation of only ∼5.2% per cycle) at a high current rate of 1224 mA g(-1), originating from the distinct core-shell synergetic effect of fast electronic delivery and from the large electrode/electrolyte contacting surfaces/interfaces provided by three-dimensional entangling coaxial CNT-based nanonetwork topology.

Ultrafast spray pyrolysis fabrication of a nanophase ZnMn2O4 anode towards high-performance Li-ion batteries

Nanophase ZnMn₂O₄ was ultrafast fabricated via a green spray pyrolysis strategy, and exhibited large initial specific discharge capacity, good rate capability, and excellent cycling stability at 1 C rate.

ZnO/C microboxes derived from coordination polymer particles for superior lithium ion battery anodes

A CPPs-derived ZnO/C hollow microboxes Li-ion anode with superior capability and rate performance was achieved by a simple solvothermal method.

Synthesis of graphene-wrapped ZnMn2O4 hollow microspheres as high performance anode materials for lithium ion batteries

A facile method for the synthesis of graphene-wrapped ZnMn₂O₄ hollow microspheres which show excellent electrochemical performance.

LiFe(MoO4)2 as a novel anode material for lithium-ion batteries

Polycrystalline LiFe(MoO4)2 is successfully synthesized by solid-state reaction and examined as anode material for lithium-ion batteries in terms of galvanostatic charge-discharge cycling, cyclic voltammograms (CV), galvanostatic intermittent titration technique (GITT), and electrochemical impedance spectroscopy (EIS). The LiFe(MoO4)2 electrode delivers a high capacity of 1034 mAh g(-1) at a current density of 56 mA g(-1) between 3 and 0.01 V, indicating that nearly 15 Li(+) ions are involved in the electrochemical cycling. LiFe(MoO4)2 also exhibits a stable capacity of 580 mAh g(-1) after experiencing irreversible capacity loss in the first several cycles. Moreover, the Li-ion storage mechanism for LiFe(MoO4)2 is suggested on the basis of the ex situ X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) at different insertion/extraction depths. A successive structural transition from triclinic structure to cubic structure is observed, and the tetrahedral coordination of Mo by oxygen in LiFe(MoO4)2 changes to octahedral coordination in Li2MoO3, correspondingly. When being discharged to 0.01 V, the active electrode is likely to be composed of Fe and Mo metal particles and amorphous Li2O due to the multielectron conversion reaction. The insights obtained from this study will benefit the design of new anode materials for lithium-ion batteries.