Synthesis of manganese-based complex as cathode material for aqueous rechargeable batteries

A low-cost and eco-friendly system based on a manganese-based complex cathode and zinc anode was demonstrated. The cathode is able to reversibly (de-)insert Zn²⁺ ions, providing a high capacity of 248 mA h g⁻¹ at 0.1 A g⁻¹. Ex situ TEM and XRD were utilized to determine the electrochemical mechanism of this high capacity cathode. Moreover, the contribution of pre-added Mn²⁺ in electrolyte to the capacity was revealed, and nearly 18.9% of the capacity is ascribed to the contribution of pre-added Mn²⁺. With the help of additive, this aqueous rechargeable battery shows outstanding electrochemical property. Its cycling performance is good with 6% capacity loss after 2000 cycles at 4.0 A g⁻¹, highlighting it as a promising system for aqueous rechargeable battery applications.

Manganese-based complex with high energy density shows a capacity retention of 94% over 2000 cycles.     

Investigation of Cu doped flake-NiO as an anode material for lithium ion batteries

Cu foil is widely used in commercial lithium ion batteries as the current collector of anode materials with excellent conductivity and stability. In this research, commercial Cu foil was chosen as the current collector and substrate for the synthesis of Cu doped flake-NiO via a traditional hydrothermal method. The effect of the ratio of Cu and the calcination temperature on the electrochemical performance of NiO was investigated. The structure and phase composition of the Cu doped flake-NiO electrode were studied through X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDAX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and inductive coupled plasma emission spectrometry (ICP). The electrochemical properties of the Cu doped flake-NiO electrode were studied through cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and a galvanostatic charge–discharge cycling technique. According to the results, the Cu-doped NiO electrode, calcined at 400 °C with a molar ratio of Cu : Ni = 1 : 8, exhibited a high reversible charge capacity. The good cycling stability and rate performance indicate that the as-prepared electrode can be applied as a potential anode for lithium ion batteries.

Cu doped flake-NiO shows excellent electrochemical performance as anode materials for lithium ion batteries.     

Silica from diatom frustules as anode material for Li-ion batteries

In spite of its insulating nature, SiO₂ may be utilized as active anode material for Li-ion batteries. Synthetic SiO₂ will typically require sophisticated synthesis and/or activation procedures in order to obtain a satisfactory performance. Here, we report on diatom frustules as active anode material without the need for extensive activation procedures. These are composed primarily of silica, exhibiting sophisticated porous structures. Various means of optimizing the performance were investigated. These included carbon coating, the addition of fluoroethylene carbonate (FEC) and vinylene carbonate (VC) to the carbonate-based electrolyte, as well as activation by an initial potentiostatic hold step. The highest capacity (723 mA h g⁻¹) was obtained with composite electrodes with pristine diatom frustules and conventional carbon black as additive, with the capacity still increasing after 50 cycles. The capacity was around 624 mA h g⁻¹ after subtraction of the contributions from the carbon black. Carbon coated diatom frustules showed a slightly lower but stable capacity after 50 cycles (600 mA h g⁻¹ after subtraction of contributions from the carbon coating and the carbon black). By the use of electrochemical characterization methods, as well as post-mortem studies, differences in reaction mechanisms could be identified and attributed to the operating and processing parameters.

Silica derived from algae was used as anode material in Li-ion batteries, giving a capacity of more than 700 mA h g⁻¹.     

Ferrocene-functionalized polyheteroacenes for the use as cathode active material in rechargeable batteries

Herein we report the synthesis and characterization of new conjugated polymers bearing redox-active pendant groups for applications as cathode active materials in secondary batteries. The polymers comprise a ferrocene moiety immobilized at a poly(cyclopenta[2,1-b:3,4-b′]dithiophene) (pCPDT, P1) or a poly(dithieno[3,2-b:2′,3′-d]pyrrole) (pDTP, P2) backbone via an ester or an amide linker. Electrochemical and oxidative chemical polymerizations were performed in order to investigate the redox behaviour of the obtained polymers P1 and P2 and to synthesize materials on gram-scale for battery tests, respectively. During galvanostatic cycling in a typical battery environment, both polymers showed high reversible capacities of 90% and 87% of their theoretical capacity and excellent capacity retentions of 84% and 97% over 50 cycles.

Redox-active ferrocene moieties were immobilized on conjugated polyheteroacenes for the application as cathode active material in organic secondary batteries.     

Facile synthesis of Camellia oleifera shell-derived hard carbon as an anode material for lithium-ion batteries

A comparatively facile and ecofriendly process has been developed to synthesize porous carbon materials from Camellia oleifera shells. Potassium carbonate solution (K₂CO₃) impregnation is introduced to modify the functional groups on the surface of Camellia oleifera shells, which may play a role in promoting the development of pore structure during carbonization treatment. Moreover, a small amount of naturally embedded nitrogen and sulfur in the Camellia oleifera shells can also bring about the formation of pores. The Camellia oleifera shell-derived carbon has a large specific surface area of 1479 m² g⁻¹ with a total pore volume of 0.832 cm³ g⁻¹ after being carbonized at 900 °C for 1 h. Furthermore, when used as an anode for lithium-ion batteries, the sample shows superior electrochemical performance with a specific capacity of 483 mA h g⁻¹ after 100 cycles measured at 200 mA g⁻¹ current density. Surprisingly, the specific capacity is even gradually increased with cycling. In addition, this sample exhibits almost 100% retention capacity after 250 cycles at a current density of 200 mA g⁻¹.

Bio-waste Camellia oleifera shells (COS) are converted into porous carbon by a two-step method.     

Facile synthesis of perovskite CeMnO3 nanofibers as an anode material for high performance lithium-ion batteries

A facile synthesis of perovskite-type CeMnO₃ nanofibers as a high performance anode material for lithium-ion batteries was demonstrated. The nanofibers were prepared by the electrospinning technique. The characterization of CeMnO₃ nanofibers was carried out by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy. SEM images manifested nanofibers with a diameter of 470 nm having a rough surface with a porous structure. TEM images were consistent with the observations from the SEM images. The electrochemical properties of CeMnO₃ perovskite in lithium-ion batteries were investigated. The CeMnO₃ anode exhibited a discharge capacity of 2159 mA h g⁻¹ with a coulombic efficiency of 93.79%. In addition, a high cycle stability and a capacity of 276 mA h g⁻¹ at the current density of 1000 mA g⁻¹ can be effectively maintained due to the high Li⁺ conductivity in the CeMnO₃ anode. This study could provide an efficient and potential application of perovskite-type CeMnO₃ nanofibers in lithium-ion batteries.

A facile synthesis of perovskite-type CeMnO₃ nanofibers as a high performance anode material for lithium-ion batteries was demonstrated.     

Hierarchical non-woven fabric NiO/TiO2 film as an efficient anode material for lithium-ion batteries

Hierarchical non-woven fabric NiO/TiO₂ film is prepared using a facile two-step synthesis by electrospinning and subsequent hydrothermal reaction to yield TiO₂ film decorated with NiO nanosheets. As an anode material for Li-ion batteries, the NiO/TiO₂ composite exhibits discharge and charge capacities of 1251.3 and 1284.3 mA h g⁻¹, with good cycling performance and rate capability. Characterization shows that the NiO nanosheets are distributed on the surface of the TiO₂ nanofibers. The total specific capacity of NiO/TiO₂ is higher than the sum of pure TiO₂ and NiO, indicating a positive synergistic effect of TiO₂ and NiO on the improvement of electrochemical performance. The results suggest that non-woven fabric NiO/TiO₂ film is a promising anode material for lithium ion batteries.

Positive synergistic effect of TiO₂ and NiO of NiO/TiO₂ non-woven fabric electrode improves the electrochemical performance.     

A self-assembled silicon/phenolic resin-based carbon core–shell nanocomposite as an anode material for lithium-ion batteries

Silicon, with advantages such as high theoretical capacity and relatively low working potential, has been regarded as promising when it is used for lithium-ion battery anodes. However, its practical application is impeded by the intrinsic low electrical conductivity and the dramatic volume change during the lithiation/delithiation process, which leads to a rapid capacity fading of the electrode. In this regard, we design silicon nanoparticles homogeneously coated with a phenolic resin-based carbon layer as a core–shell nanocomposite via a facile self-assembly method followed by carbonization. The surrounding carbon shell, confirmed by transmission electron microscopy and Raman spectroscopy, is not only beneficial to the formation of a stable solid electrolyte interface film, but the electrical conductivity of the electrode is also enhanced. A high and stable specific capacity of nearly 1000 mA h g⁻¹ is achieved at C/3 after 200 cycles with a coulombic efficiency of >99.6%. The entire synthesis process is quite simple and easy to scale up, thus having great potential for commercial applications.

A self-assembled silicon/phenolic resin-based carbon core–shell nanocomposite is reported, which exhibits a high and stable reversible capacity and good rate capability.     

First-principles calculations of an asymmetric MoO2/graphene nanocomposite as the anode material for lithium-ion batteries

Previous work on the synthesis and preparation of MoO₂/graphene nanocomposites (MoO₂/G) indicates that MoO₂/G is a good anode material for lithium-ion batteries (LIBS). In this work, we used larger super-cells than those used previously to theoretically construct an asymmetric MoO₂/G nanocomposite with smaller lattice mismatch. We then calculated the structural, electronic and Li atom diffusion properties of MoO₂/G using first-principles calculations based on density functional theory. The results show that asymmetric MoO₂/G has metallic properties, good stability and a low Li atom diffusion barrier because of the charge transfer induced by van der Waals interactions. The Li diffusion barriers in the interlayer of MoO₂/G are in the range of 0.02–0.29 eV, depending on the relative positions of the Li atom and the MoO₂ and the C atoms in the graphene layer. The Li diffusion barriers on the outside layers of the MoO₂/G nanocomposite are smaller than those of its pristine materials (MoO₂ and graphene). These results are consistent with experimental results. The adsorption of Li atoms in the interlayer of the nanocomposite further promotes the adsorption of Li atoms on the outside sites of the MoO₂ layer. Hence, the specific capacity of the MoO₂/G nanocomposite is larger than 1682 mA h g⁻¹. These properties all indicate that MoO₂/G is a good anode material for LIBS.

The structure of a nanocomposite constructed from MoO₂ and graphene and its Li atom adsorption and diffusion properties.     

Exploring high-energy and mechanically robust anode materials based on doped graphene for lithium-ion batteries: a first-principles study

In this study, the adsorption of Li atoms on various types of doped graphene with substituents, including boron, nitrogen, sulfur and silicon atoms, has been theoretically investigated by first-principles calculations, based on the density functional theory. We discovered that the boron-doped graphene had a greatly enhanced Li-binding energy than those of graphene with other doped atoms as well as pristine graphene, which is helpful in preventing the Li atoms from clustering during charging. The Li atom preferred to be close to the doped B or Si atom, but farther away from the substituted N and S atoms, with different stable adsorption sites. This demonstrated the different chemical interactions between the Li atoms and the distinct dopants in graphene, which was confirmed by the electron density and charge transfer analysis. However, it was found that the introduction of dopant atoms in-plane with graphene reduced the mechanical strength of the graphene anode throughout the uniaxial tension simulations. Lastly, the effect of strain on the adsorption energy of the Li atoms on doped graphene was studied, and the results illustrated that tensile strain enhances the interactions between the Li atoms and the graphene anode. These results provide theoretical guidance for the discovery and fabrication of high-energy-density anode materials with desired mechanical properties.

The adsorption of Li atoms on various types of doped graphene with substituents, including boron, nitrogen, sulfur and silicon atoms, has been theoretically investigated by first-principles calculations, based on the density functional theory.     

Three-dimensional thiophene-diketopyrrolopyrrole-based molecules/graphene aerogel as high-performance anode material for lithium-ion batteries

Herein, 3,6-di(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (TDPP) and di-tert-butyl 2,2′-(1,4-dioxo-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-2,5(1H,4H)-diyl)diacetate (TDPPA) were synthesized, which were then loaded in graphene aerogels. The as-prepared thiophene-diketopyrrolopyrrole-based molecules/reduced graphene oxide composites for lithium-ion battery (LIB) anode composites consist of DPPs nanorods on a graphene network. In relation to the DPPs part, embedding DPPs nanorods into graphene aerogels can effectively reduce the dissolution of DPPs in the electrolyte. It can serve to prevent electrode rupture and improve electron transport and lithium-ion diffusion rate, by partially connecting DPPs nanorods through graphene. The composite not only has a high reversible capacity, but also shows excellent cycling stability and performance, due to the densely distributed graphene nanosheets forming a three-dimensional conductive network. The TDPP₆₀ electrode exhibits high reversible capacity and excellent performance, showing an initial discharge capacity of 835 mA h g⁻¹ at a current density of 100 mA g⁻¹. Even at a current density of 1000 mA g⁻¹, after 500 cycles, it still demonstrates a discharge capacity of 303 mA h g⁻¹ with a capacity retention of 80.7%.

Herein, TDPP and TDPPA were synthesized and then loaded on graphene by hydrothermal method to obtain TDPP/RGO and TDPPA/RGO aerogel, which were applied as anode for LiBs.     

One-step heat treatment to process semi-coke powders as an anode material with superior rate performance for Li-ion batteries

“Turning waste into wealth” and sustainable development are bright themes of modern society. Semi-coke is mainly made up of coal but contains around 15 wt% impurities. Nevertheless, semi-coke powders with sizes smaller than 3 mm generally cannot be used in metallurgical industries and are abandoned as solid waste, resulting in environmental contamination. Herein, boron doping followed by facile one-step heat treatment in the range of 2100 to 2700 °C has been carried out to process semi-coke powder waste. Thereby, the semi-coke powders can be graphitized to give sample carbon content values of over 95%. The best product so-prepared delivered reversible capacities of 351.5 mA h g⁻¹ at 0.1C, and 322 mA h g⁻¹ at 1C. Surprisingly, the capacity was maintained at 314.3 mA h g⁻¹ after 300 cycles at 1C, giving a decline rate of only 2.4% and presenting superior rate performance.

The processed SC can deliver a capacity of 314.3 mA h g⁻¹ after 300 cycles at 1C with a decline rate of 2.4%.     

Preparation of Sn-aminoclay (SnAC)-templated Fe3O4 nanoparticles as an anode material for lithium-ion batteries

Sn-aminoclay (SnAC)-templated Fe₃O₄ nanocomposites (SnAC–Fe₃O₄) were prepared through a facile approach. The morphology and macro-architecture of the fabricated SnAC–Fe₃O₄ nanocomposites were characterized by different techniques. A constructed meso/macro-porous structure arising from the homogeneous dispersion of Fe₃O₄ NPs on the SnAC surface owing to inherent NH₃⁺ functional groups provides new conductive channels for high-efficiency electron transport and ion diffusion. After annealing under argon (Ar) gas, most of SnAC layered structure can be converted to SnO₂; this carbonization allows for formation of a protective shell preventing direct interaction of the inner SnO₂ and Fe₃O₄ NPs with the electrolyte. Additionally, the post-annealing formation of Fe–O–C and Sn–O–C bonds enhances the connection of Fe₃O₄ NPs and SnAC, resulting in improved electrical conductivity, specific capacities, capacity retention, and long-term stability of the nanocomposites. Resultantly, electrochemical measurement exhibits high initial discharge/charge capacities of 980 mA h g⁻¹ and 830 mA h g⁻¹ at 100 mA g⁻¹ in the first cycle and maintains 710 mA h g⁻¹ after 100 cycles, which corresponds to a capacity retention of ∼89%. The cycling performance at 100 mA g⁻¹ is remarkably improved when compared with control SnAC. These outstanding results represent a new direction for development of anode materials without any binder or additive.

Sn-aminoclay (SnAC)/Fe₃O₄ NPs – a promising hybrid electrode to offer great electrochemical performance with a high initial discharge of 980 mA h g⁻¹ and good capacity retention of 89% after 100 cycles.     

Application of soot discharged from the combustion of marine gas oil as an anode material for lithium ion batteries

Many studies have recently investigated the characteristics of combustion products emitted from ships and onshore plant facilities for use as energy sources. Most combustion products that have been reported until now are from heavy oils, however, no studies on those from light oils have been published. This study attempted to use the combustion products from the light oils from naval ships as anode materials for lithium ion batteries (LIBs). These products have a carbon black morphology and were transformed into highly crystalline carbon structures through a simple heat treatment. These new structured materials showed reversible capacities of 544, 538, 510, 485, 451 and 395 mA h g⁻¹ at C-rates of 0.1, 0.2, 0.5, 1.0, 2.0 and 5.0C, respectively, and excellent rate performance. These findings were the result of a combination hierarchical pores ranging from the meso- to macroscale and the high capacitive charge storage behavior of the soot. The results of this study prove that annealed soot with a unique multilayer graphite structure shows promising electrochemical performance suitable for the production of low-cost, high-performance LIB anode materials.

Many studies have recently investigated the characteristics of combustion products emitted from ships and onshore plant facilities for use as energy sources.     

Density functional theory calculations for evaluation of phosphorene as a potential anode material for magnesium batteries

We have systematically investigated black phosphorus and its derivative – a novel 2D nanomaterial, phosphorene – as an anode material for magnesium-ion batteries. We first performed Density Functional Theory (DFT) simulations to calculate the Mg adsorption energy, specific capacity, and diffusion barriers on monolayer phosphorene. Using these results, we evaluated the main trends in binding energy and voltage as a function of Mg concentration. Our studies revealed the following findings: (1) Mg bonds strongly with the phosphorus atoms and exists in the cationic state; (2) Mg diffusion on phosphorene is fast and anisotropic with an energy barrier of only 0.09 eV along the zigzag direction; (3) the theoretical specific capacity is 865 mA h g⁻¹ with an average voltage of 0.833 V (vs. Mg/Mg²⁺), ideal for use as an anode. Given these results, we conclude that phosphorene is a very promising anode material for Mg-ion batteries. We then expand our simulations to the case of bulk black phosphorus, where we again find favorable binding energies. We also find that bulk black phosphorous must overcome a structural stress of 0.062 eV per atom due to a volumetric expansion of 33% during magnesiation. We found that the decrease in particle size is good to increase its specific capacity.

Phosphorene adsorbs Mg to form a stable product MgP₂, delivering a theoretical specific capacity of 865 mA h g⁻¹.     

Proton solvent-controllable synthesis of manganese oxalate anode material for lithium-ion batteries

Manganese oxalates with different structures and morphologies were prepared by the precipitation method in a mixture of dimethyl sulfoxide (DMSO) and proton solvents. The proton solvents play a key role in determining the structures and morphologies of manganese oxalate. Monoclinic MnC₂O₄·2H₂O microrods are prepared in H₂O-DMSO, while MnC₂O₄·H₂O nanorods and nanosheets with low crystallinity are synthesized in ethylene glycol-DMSO and ethanol-DMSO, respectively. The corresponding dehydrated products are mesoporous MnC₂O₄ microrods, nanorods, and nanosheets, respectively. When used as anode material for Li-ion batteries, mesoporous MnC₂O₄ microrods, nanorods, and nanosheets deliver a capacity of 800, 838, and 548 mA h g⁻¹ after 120 cycles at 8C, respectively. Even when charged/discharged at 20C, mesoporous MnC₂O₄ nanorods still provide a reversible capacity of 647 mA h g⁻¹ after 600 cycles, exhibiting better rater performance and cycling stability. The electrochemical performance is greatly influenced by the synergistic effect of surface area, morphology, and size. Therefore, the mesoporous MnC₂O₄ nanorods are a promising anode material for Li-ion batteries due to their good cycle stability and rate performance.

Manganese oxalates with different structures and morphologies were prepared by the precipitation method in a mixture of dimethyl sulfoxide (DMSO) and proton solvents.     

High-Ni cathode material improved with Zr for stable cycling of Li-ion rechargeable batteries

The Zr solvent solution method, which allows primary and secondary particles of LiNi_0.90Co_0.05Mn_0.05O₂ (NCM) to be uniformly doped with Zr and simultaneously to be coated with an Li₂ZrO₃ layer, is introduced in this paper. For Zr doped NCM, which is formed using the Zr solvent solution method (L-NCM), most of the pinholes inside the precursor disappear owing to the diffusion of the Zr dopant solution compared with Zr-doped NCM, which is formed using the dry solid mixing method from the (Ni_0.90Co_0.05Mn_0.05)(OH)₂ precursor and the Zr source (S-NCM), and Li₂ZrO₃ is formed at the pinhole sites. The mechanical strength of the powder is enhanced by the removal of the pinholes by the formation of Li₂ZrO₃ resulting from diffusion of the solvent during the mixing process, which provides protection from cracking. The coating layer functions as a protective layer during the washing process for removing the residual Li. The electrochemical performance is improved by the synergetic effects of suitable coatings and the enhanced structural stability. The capacity-retentions for 2032 coin cells are 86.08%, 92.12%, and 96.85% at the 50^th cycle for pristine NCM, S-NCM, and L-NCM, respectively. The superiority of the liquid mixing method is demonstrated for 18 650 full cells. In the 300^th cycle in the voltage range of 2.8–4.35 V, the capacity-retentions for S-NCM and L-NCM are 77.72% and 81.95%, respectively.

The Zr solvent solution method, which allows primary and secondary particles of LiNi_0.90Co_0.05Mn_0.05O₂ (NCM) to be uniformly doped with Zr and simultaneously to be coated with an Li₂ZrO₃ layer, is introduced in this paper.     

Double-layer carbon protected CoS2 nanoparticles as an advanced anode for sodium-ion batteries

Cobalt disulfides with high theoretical capacity are regarded as appropriate anode materials for sodium ion batteries (SIBs), but their intrinsically low conductivity and large volume expansion lead to a poor electrochemical performance. In this work, graphitic carbon coated CoS₂ nanoparticles are encapsulated in bamboo-like carbon nanotubes by pyrolysis and sulfidation process. Graphitic carbon can improve the electrical conductivity and prevent the agglomeration of CoS₂ nanoparticles. Meanwhile, bamboo-like carbon nanotubes can serve as conductive skeleton frames to provide rapid and constant transport pathways for electrons and offer void space to buffer the volume change of CoS₂ nanoparticles. The advanced anode material exhibits a long-term capacity of 432.6 mA h g⁻¹ at 5 A g⁻¹ after 900 cycles and a rate capability of 419.6 mA h g⁻¹ even at 10 A g⁻¹ in the carbonate ester-based electrolyte. This avenue can be applicable for preparing other metal sulfide/carbon anode materials for sodium-ion batteries.

The outstanding electrochemical performance is ascribed to the novel structure design of CoS₂@GC@B-CNT.     

A nanostructured SnO2/Ni/CNT composite as an anode for Li ion batteries

A SnO₂/Ni/CNT nanocomposite was synthesized using a simple one-step hydrothermal method followed by calcination. A structural study via XRD shows that the tetragonal rutile structure of SnO₂ is maintained. Further, X-ray photoelectron spectroscopy (XPS) and Raman studies confirm the existence of SnO₂ along with CNTs and Ni nanoparticles. The electrochemical performance was investigated via cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge measurements. The nanocomposite has been used as an anode material for lithium-ion batteries. The SnO₂/Ni/CNT nanocomposite exhibited an initial discharge capacity of 5312 mA h g⁻¹ and a corresponding charge capacity of 2267 mA h g⁻¹ during the first cycle at 50 mA g⁻¹. Pristine SnO₂ showed a discharge/charge capacity of 1445/636 mA h g⁻¹ during the first cycle at 50 mA g⁻¹. This clearly shows the effects of the optimum concentrations of CNTs and Ni. Further, the nanocomposite (SnNiCn) shows a discharge capacity as high as 919 mA h g⁻¹ after 210 cycles at a current density of 400 mA g⁻¹ in a Li-ion battery set-up. Thus, the obtained capacity from the nanocomposite is much higher compared to pristine SnO₂. The higher capacity in the nanoheterostructure is due to the well-dispersed nanosized Ni-decorated stabilized SnO₂ along with the CNTs, avoiding pulverization as a result of the volumetric change of the nanoparticles being minimized. The material accommodates huge volume expansion and avoids the agglomeration of nanoparticles during the lithiation and delithiation processes. The Ni nanoparticles can successfully inhibit Sn coarsening during cycling, resulting in the enhancement of stability during reversible conversion reactions. They ultimately enhance the capacity, giving stability to the nanocomposite and improving performance. Additionally, the material exhibits a lower Warburg coefficient and higher Li ion diffusion coefficient, which in turn accelerate the interfacial charge transfer process; this is also responsible for the enhanced stable electrochemical performance. A detailed mechanism is expressed and elaborated on to provide a better understanding of the enhanced electrochemical performance.

SnO₂/Ni/CNT nanocomposite approach has been demonstrated which confers shielding against volume expansion due to the use of optimum % of Ni & CNT exhibiting superior cycling stability and rate capabilities of the stable electrode structure.     

Carbon-coated SnO2 riveted on a reduced graphene oxide composite (C@SnO2/RGO) as an anode material for lithium-ion batteries

The research on graphene-based anode materials for high-performance lithium-ion batteries (LIBs) has been prevalent in recent years. In the present work, carbon-coated SnO₂ riveted on a reduced graphene oxide sheet composite (C@SnO₂/RGO) was fabricated using GO solution, SnCl₄, and glucose via a hydrothermal method after heat treatment. When the composite was exploited as an anode material for LIBs, the electrodes were found to exhibit a stable reversible discharge capacity of 843 mA h g⁻¹ at 100 mA g⁻¹ after 100 cycles with 99.5% coulombic efficiency (CE), and a specific capacity of 485 mA h g⁻¹ at 1000 mA g⁻¹ after 200 cycles; these values were higher than those for a sample without glucose (SnO₂/RGO) and a pure SnO₂ sample. The favourable electrochemical performances of the C@SnO₂/RGO electrodes may be attributed to the special double-carbon structure of the composite, which can effectively suppress the volume expansion of SnO₂ nanoparticles and facilitate the transfer rates of Li⁺ and electrons during the charge/discharge process.

The combined action of GO and glucose makes the SnO₂ dispersed uniformly. The synergistic effect of the unique double-carbon structure can effectively improve the electrical conductivity of the SnO₂ and strengthen lithium storage capability.