Anode Material For LIBs Research Articles

Cobalt oxide based inorganic-organic hybrid composite as novel anodic material for ultra-stable Li-ion battery

Energy demands for modern society with improved life quality are totally based on materials, which are fossils free to overcome the challenges affecting the health and climate. In the present work, a 3D hierarchical composite of Cobalt oxide@Copper Acetate@Benzenetricarboxylate (Co@CuAc@BTC) is prepared by using Cobalt oxide nanoparticles as a base material to act as an efficient anode material for LIBs. The coating of metallic organic frame work (MOF) of BTC and Cu(II)Ac alternatively, was applied through versatile layer-by-layer (LBL) assembly method. Presence of π-conjugated benzene rings in the composite was identified by analysis of FTIR. Face centered cubic crystal structure aligned with crystallographic pattern was confirmed by pXRD analysis. The surface morphology and elemental composition was predicted by SEM-EDS, Specific surface area through BET and the thermal stability through TGA analysis. Nyquist plots show that the charge transfer resistance Rct for composite is lower (377.2 Ω) comparative to Co-oxide Nps (590.2 Ω). Electrochemical studies showed that Co@CuAc@BTC composite, as an active anodic material for LIBs, exhibited a higher discharge capacity of 1380 mA h/g and remarkably good rate performance with a charge capacity of 1060 mA h/g at 100 mA/g with 78% (10% increase comparative to that of Co-oxide Nps) initial columbic efficiency. At 100th cycle material show 97% columbic efficiency with reversible capacity of 1064 mA h/g. outstanding electrochemical performance of Co@CuAc@BTC composite offers an easy, large-scale and low cost route to produce anode materials for LIBs.

Investigation on electrochemical performance of striped, β12 and χ3 Borophene as anode materials for lithium-ion batteries

By developing next-generation lithium-ion batteries (LIBS), demand for exploring novel anode materials with exclusive electrochemical features and ultra-high capacity is increasing. In the current research, first-principles theory, and density functional theory (DFT) calculations were conducted to extensively investigate and compare the capability of three different borophene nanolayers, including striped, β12, and χ3 borophene, as a novel candidate for anode electrode in LIBs. We first predicted the most preferential Li atom adsorption sites on the three borophene structures. The predicted average formation energies for striped, β12, and χ3 borophene were obtained 3.123, 3.184, and 3.216 eV, respectively. The positive value of formation energy exhibits the sufficient stability of the structures. Moreover, the negative adsorption energy proved that Li atom insertion on all borophene monolayers is thermodynamically favorable. In order to simulate the lithiation process, we gradually increased the concentration of Li atoms. We found that the fully lithiated striped, β12 and χ3 borophenes could provide ultra-high specific capacities of 1700, 1983, and 1859 mAh/g, respectively. Structural analysis proved that the surface area expansion rate of the striped borophene in a fully lithiated state was 1%, which was lower than those of β12 and χ3 borophene with 3.33% and 2.63%, respectively. The analyses of electronic properties confirmed that borophenes were inherently metallic and superior ion conductive agents, even after fully lithiated state. Ion diffusion was studied using Nudged elastic band method and the value of diffusion energy barrier ranged from 0.03 to 0.36 eV which was lower than other promising 2D anode materials. Furthermore, open-circuit voltage results demonstrated that the electronic potential of modeled borophenes was low enough to be in the acceptable range of under 1.2V. All these reports exhibited that borophene nanolayers with excellent specific capacity and superior conductivity were desired candidates for anode materials of next generation LIBs.

Photo-Initiated in situ synthesis of polypyrrole Fe-Coated porous silicon microspheres for High-performance Lithium-ion battery anodes

A simple and environmentally friendly photoinitiated fabrication approach based on the photoelectric effect of semiconductor silicon is designed to synthesize yolk-shell like polypyrrole-iron coated porous silicon microspheres (PSi@PPy-Fe) as anode materials for LIBs. The polymerization of pyrrole monomers only occurs on the interface of silicon matrix where the vacancies are available, which effectively avoids the production of free PPy-Fe particles. XPS and first-principles calculations reveal that both the hydrogen-bond interaction and the covalent linkage are formed between Si and PPy-Fe layer, which is of great significance for maintaining good contact and strengthening the structure stability. It is demonstrated that the PPy-Fe coating may accelerate charge transfer and ion diffusion as well as prevent the Si-based materials peeling off from Cu collector. More importantly, the PPy-Fe coating could alleviate the violent structural expansion of Si anode, thus ameliorating the mechanical strength of the electrode. Consequently, the as-prepared yolk-shell like polypyrrole-iron coated porous silicon microspheres present outstanding cycling ability (1853.7 mAh/g after 200 cycles at 1 A/g) and superior rate capability (1558.4 mAh/g at 4 A/g). This work indicates that the photochemical modification strategy for Si may have a bright prospect in a wide range of fields.

Metal Oxide Wrapped by Reduced Graphene Oxide Nanocomposites as Anode Materials for Lithium-Ion Batteries.

The reduced graphene oxide/iron oxide (rGO/Fe2O3) and reduced graphene oxide/cobalt oxide (rGO/Co3O4) composite anodes have been successfully prepared through a simple and scalable ball-milling synthesis. The substantial interaction of Fe2O3 and Co3O4 with the rGO matrix strengthens the electronic conductivity and limits the volume variation during cycling in the rGO/Fe2O3 and rGO/Co3O4 composites because reduced graphene oxide (rGO) helps the metal oxides (MOs) to attain a more efficient diffusion of Li-ions and leads to high specific capacities. As anode materials for LIBs, the rGO/Fe2O3 and rGO/Co3O4 composites demonstrate overall superb electrochemical properties, especially rGO/Fe2O3T-5 and rGO/Co3O4T-5, showcasing higher reversible capacities of 1021 and 773 mAhg-1 after 100 cycles at 100 mAg-1, accompanied by the significant rate performance. Because of their superior electrochemical efficiency, high capacity and low cost, the rGO/Fe2O3 and rGO/Co3O4 composites made by ball milling could be outstanding anode materials for LIBs. Due to the excellent electrochemical performance, the rGO/Fe2O3 and rGO/Co3O4 composites prepared via ball milling could be promising anode materials with a high capacity and low cost for LIBs. The findings may provide shed some light on how other metal oxides wrapped by rGO can be prepared for future applications.

Facile synthesis of microwave-etched Ti3C2 MXene/activated carbon hybrid for lithium-ion battery anode

In this study, we synthesized MXene hybrid electrodes using a novel strategy to generate a synergistic effect between the respective components. Initially, a few-layered Ti3C2 MXene was prepared via microwave-assisted in-situ etching. The AC to Ti3C2 MXene ratio is varied to be 10:0, 9:1, 8:2, and 7:3 in order to maximize electrochemical efficiency. As an anode material for LIBs, the hybrid AC_Ti3C2 (8:2) electrode exhibits the highest initial specific capacity of 1194.2 mAh/g discharged at a current density of 0.2 A/g and maintains over 841.8 mAh/g after 80 consecutive cycles (with a Coulombic efficiency of ∼100 %). An increase in the discharge capacity of the hybrid electrode from 750.5 to 881.9 mAh/g when the current density changed from 1 to 0.2 A/g suggests the excellent rate capability of the AC_Ti3C2 (8:2) hybrid electrode. Furthermore, electrochemical impedance spectroscopic analysis of AC_Ti3C2 (8:2) shows a low charge transfer resistance (Rct) of 8.52 Ω, indicating good conductivity of the hybrid electrode. The work presented here confirms that the AC can be used as an interlayer spacer in synthesizing Ti3C2 MXene hybrids and have excellent application prospects for the next-generation LIBs.

Electrochemical graphitization transformation of deposited carbon for Li-ion storage: sustainable energy utilization from coke oven solid waste

Deposited carbon was converted into flake graphite by molten salt electrolysis. Deposited carbon-derived graphite can be used as an anode material for LIBs.

Molecular precursor mediated selective synthesis of phase pure cubic InSe and hexagonal In2Se3 nanostructures: new anode materials for Li-ion batteries.

Indium selenides (InSe and In2Se3) have earned a special place among the 2D layered metal chalcogenides owing to their nontoxic nature and favourable carrier mobility. Additionally, they are also being projected as next generation battery anodes with high theoretical lithium-ion storage capacities. While the development of indium selenide-based batteries is still in its embryonic stage, a simple and easily scalable synthetic pathway to access these materials is highly desirable for energy storage applications. This study reports a controlled synthetic route to nanometric cubic InSe and hexagonal In2Se3 materials through proper choice of coordinating solvents from a structurally characterized air and moisture stable single source molecular precursor: tris(4,6-dimethyl-2-pyrimidylselenolato)indium(III). The crystal structure, phase purity, composition, morphology and band gap of the nanomaterials were thoroughly evaluated by pXRD, energy dispersive X-ray spectroscopy (EDS), electron microscopy (SEM and TEM), and diffuse reflectance spectroscopy (DRS), respectively. The pristine InSe and In2Se3 nanostructures have been employed as anode materials in lithium-ion batteries (LIBs). Both the cells deliver reasonably high initial discharge capacities with a cyclability of 200 and 620 cycles for cubic InSe and hexagonal In2Se3 respectively with ∼100% coulombic efficiency.

Carbon encapsulated hybrid Fe-based nanostructure with durable lithium storage

N-doped carbon coated Fe3O4 was synthesized from MIL-53(Fe) coated PDA as a precursor and used as an anode material for LIBs.

Continuous wet chemical synthesis of Mo(C,N,O)x as anode materials for Li-ion batteries

Inorganic–organic hybrid materials synthesized in the microjet reactor by a facile precipitation reaction at room temperature serve as precursors for mixed anionic carbide-nitride-oxides. These materials were used as LIB anode materials.

TiFeNb10O29-δ anode for high-power and durable lithium-ion batteries.

A new Fe-substituted TiFeNb10O29-δ (TFNO) anode is proposed. TFNO possesses a defective and polycrystalline ReO3 Roth-Wadsley shear structure with a slightly larger lattice volume. Electrochemical behavior results and density functional theory (DFT) calculations show that TFNO can facilitate the kinetics of electron/Li+ transportation and demonstrates pseudocapacitive behavior. Consequently, TFNO exhibits superior high rate capacity and cycling stability compared to pristine TNO, offering 100 mA h g-1 at an ultrahigh rate of 50C and a high capacity retention of 86.7% over 1000 cycles at 10C. This work reveals that TFNO could be a promising anode material for fast-charging, stable, and safe LIBs.

Blue phosphorene/graphdiyne heterostructure as a potential anode for advanced lithium-ion batteries: First-principle investigation

Blue phosphorene has triggered enormous research effort as an anode for Li-ion batteries due to its large surface and high capacity. However, its application is hindered by poor electrical conductivity, mechanical properties and mobility. Graphdiyne exhibits excellent mechanical properties and high storage capacity but low Li-ion mobility. Herein, we designed blue phosphorene/graphdiyne (BlueP/GDY) heterostructure as a potential anode material for LIB based on denstity functional theory. We demonstrated that BlueP/GDY heterostructure exhibits good thermodynamics stability and enhanced elastic stiffness (Young’s modulus is 215.9 N/m), which can effectively avoid electrode cracking and pulverization. Synergistic effect between BlueP and GDY significantly enhanced binding strength of Li for composite compared with isolated BlueP and GDY. The transition of semiconducting to metallic induced by Li intercalation suggested better metallic conductivity for fast electron transport. Furthermore, BlueP/GDY heterostructure delivers high theoretical specific capacity (761.76 mA·h·g−1) and rather small Li-ion diffusion energy barriers (0.11 eV), which is estimated to be 105 times faster than that on isolated BlueP and GDY at room temperature, indicating excellent rate performance for BlueP/GDY anode. Therefore, it is expected that BlueP/GDY heterostructure has great potential in LIBs with excellent mechanical stability, good electrical conductivity, high capacity and fast Li-ion mobility.

Self-swelling derived frameworks with rigidity and flexibility enabling high-reversible silicon anodes

ABSTRACT Silicon is recognized as the most advantageous next-generation anode material for LIBs in terms of its extremely high theoretical capacity and appropriate operating voltage. However, the application of Si anode is limited by huge volume expansion emerging with cycling, which in turn induces the collapse of the electrode structure, resulting in rapid capacity decay. Here, we report a strategy using self-swelling artificial laponite to prepare a laponite/MXene/CNT composite framework with both rigidity and flexibility, which can excellently address these challenges of Si anode. The self-swelling artificial laponite participates in the construction of hierarchical and porous structures, providing sufficient buffer space to mitigate the volume expansion of the Li x Si alloying reaction. Meanwhile, tough and tightly cross-linked silicate nanosheets can improve the mechanical strength of the framework for strong structural stability. More importantly, the negative charge between the layers of artificial laponite can effectively promote fast Li-ion transport in the electrode. This free-standing silicon anode enables the preparation of high areal capacity electrodes to further enhance the energy density of LIBs and a higher reversible capacity of 2381.8 mAh/g at 0.1 C after 50 cycles with an initial coulombic of 85.6%. This work provides a simple and practical fabrication strategy for developing high-performance Si-based batteries, which can speed up their commercialization. A 3D free-standing silicon anode with both rigidity and flexibility has been constructed via self-swelling artificial laponite, which enables the preparation of high areal capacity electrodes to further enhance the energy density of LIBs.

Alpha-Germanium Nanolayers for High-Performance Li-ion Batteries.

The exfoliation of tridimensional crystal structures has recently been considered a new source of bidimensional materials. The new approach offers the possibility of dramatically enlarging the library of bidimensional materials, but the number of nanolayers produced so far is still limited. Here, we report for the first time the use of a new type of material, α-germanium nanolayers (2D α-Ge). The 2D α-Ge is obtained by exfoliating crystals of α-germanium in a simple one-step procedure assisted by wet ball-milling (gram-scale fabrication). The α-germanium nanolayers have been tested as anode material for high-performance LIBs. The results show excellent performance in semi-cell configuration with a high specific capacity of 1630 mAh g-1 for mass loading of 1 mg cm-2 at 0.1 C. The semi-cell was characterized by a constant current rate of 0.5 C during 400 cycles and different scan rates (0.1 C, 0.5 C, and 1 C). Interestingly, the structural characterization, including Raman spectroscopy, XRPD, and XPS, concludes that 2D α-Ge largely retains its crystallinity after continuous cycling. These results can be used to potentially apply these novel 2D germanium nanolayers to high-performance Li-ion batteries.

Nanowires-Assembled TiO2 Nanorods Anchored on Multilayer Graphene for High-Performance Anodes of Lithium-Ion Batteries.

Multilayer graphene (MLG) prepared via ultrasonic exfoliation has many advantages such as its low-cost and defect-free nature, high electronic conductivity, and large specific surface area, which make it an apt conductive substrate for TiO2 composites. To synthesize graphene/TiO2 hybrids, traditional methods that greatly depend on the chemical bond of oxygen-containing functional groups on graphene with titanium cations are not applicable due to the absence of these functional groups on MLG. In this work, a facile chemical method is developed to directly deposit TiO2 on the MLG surface without the introduction of chemically active groups. With this method, four types of TiO2 materials, that is pure anatase TiO2 nanoparticles, a mixture of anatase TiO2 nanoparticles and rutile TiO2 nanoflowers, pure rutile TiO2 nanoflowers, and pure rutile TiO2 nanorods, are homogeneously anchored on the MLG surface by controlling the amount of HCl in the reactant. Interestingly, the rutile TiO2 nanorods in the TiO2/MLG composite are assembled by many TiO2 nanowires with an ultra-small diameter and ultra-long length, which provides a better synergetic effect for high performances as LIB anodes than other composites. A specific capacity of 631.4 mAh g−1 after 100 cycles at a current density of 100 mA g−1 is delivered, indicating it to be a valuable LIB anode material with low cost and high electrochemical performances.

MoS2—Carbon Materials Composite with Dual Phase of MoS2 and Their Application for Anode of Lithium Ion Battery

Carbon materials such as graphite, graphene, and CNT are mainly used as anode materials for LIBs because of their wide surface area and excellent stability in Lithium Ion Battery operation. However, graphite, which is mainly used as an anode material, has a very low theoretical capacity of 372 mAh/g. As high-capacity LIBs are increasingly needed like electric vehicles, many studies are being conducted to increase LIB capacity. For example, research on Si anode materials is attracting attention, and Si has a high theoretical capacity of ~4200 mAh/g. However, since there is a fatal disadvantage of volume expansion in cycle performance, stability can be a major defect in the driving condition of LIB.Transition Metal Dichalgogenides (TMD) materials are attraction a lot of attention as various energy materials such as HER and ORR as well as LIB. Their structural characteristics, low price, and high capacity in terms of energy storage make them very attractive to study as a new anode material for LIB batteries. MoS2 belonging to the TMD material is known to have a theoretical capacity of 670 mAh/g. In particular, MoS2 has a single layer structure, and this single layer structure is coupled by weak van der walls force. These properties are very advantageous for exfoliating MoS2 to form a layer-by-layer form with other materials. MoS2 is known to have a typical 1T, 2H structure. However, MoS2, which exists in a stable phase, generally has a 2H structure and has semiconducting properties. Therefore, it is less conductive than graphene, which can be an obstacle to being used as an anode. MoS2 is known to have a typical 1T, 2H structure. However, MoS2, which exists in a stable phase, generally has a 2H structure and has semiconducting properties. Therefore, it is less conductive than graphene, which can be an obstacle to being used as an anode. 1T structure is known to have very good conductivity because it has conductive properties. Therefore, when used as an anode, it has many advantages in that it has conductivity, but since it is a metastable structure, it can be converted to 2H very easily, so it is not easy to maintain the structure.In this study, the synthesis of MoS2 and graphene composites was performed in one pot using a chemical exfoliation method. In addition, it was possible to stably maintain the metastable 1T structure of MoS2 by using graphene as a support material through a post-treatment process in this process. The diffusion of Li+ was promoted by having a 1T structure with a wide interfacial spacing and high conductivity, and superior conductivity and high capacity were stably maintained compared to a composite having a 2H single phase. Through this, a stable and high-capacity anode material was realized using the high energy storage capacity of MoS2 and the stability of graphene.

Quantification of Lithium Inventory Loss in Micro Silicon Anode Via Titration-Gas Chromatography

Enabling silicon as an anode material for LIBs has been largely impeded by the severe volume changes it undergoes during cell operation, causing continuous Li inventory loss . Therefore, It is important to understand and quantify various sources of capacity fade in order to design effective mitigation strategies. In this work, we used a method based on Titration Gas Chromatography (TGC) to show a non-linear volume expansion in µSi anode during the electrochemical lithiation process. The severe volume expansion towards the end of lithiation leads to the accelerated SEI formation and thus leading to the conductive pathway loss, which results in a large amount of trapped Li-Si alloy accumulation. This TGC method was also applied to study μSi anodes with two different binders namely: Sodium Carboxymethyl Cellulose (CMC-Na) and Polyacrylic Acid (PAA). The main reason for capacity loss for the anode with CMC-Na binder was the trapped Li-Si alloy, which was reduced by using a more mechanically robust PAA binder. The concept of State of Charge (SoC) control was also investigated in µSi-LFP full cells with both the binders by tuning the N/P ratios from 1.5 to 3. The results showed that binder robustness is important for mitigating the trapped Li-Si alloy accumulation in µSi anode. Additionally, the effect of particle size of active material on trapped Li-Si accumulation was also investigated using the TGC method Figure: Cycle performance of µSi- CMC-Na-LFP full-cell with various N/P ratios (b) Cycle performance of µSi-PAA-LFP full-cell with various N/P ratios (c) TGC Data for Lithium inventory loss of full cell after 1st cycle for various N/P ratios (d) TGC Data for Lithium inventory loss of full cell after 10 cycles for various N/P ratios Figure 1

Scalable Synthesis of High Performance Silicon Anode by Impregnation of Pitch in Nanoporous Silicon

Silicon (Si) has been regarded as one of the most promising anode materials for the next generation LIBs with high energy density because it has 10 times higher theoretical specific capacity (4200 mAh/g) than that of graphite. However, severe volume change (~300%) of Si during lithiation and delithiation hinders the practical application of Si anode by 1) particle fracture and pulverization, 2) disintegration of electrode, and 3) continuous electrolyte-decomposition at the newly exposed Si surface. A novel process has been developed for the preparation of porous Si/C composite-based anode which demonstrate highly stable cycling stability. The enabling factor is a wet chemical, low temperature pitch coating process that uses readily available, low-cost, and abundant precursors. The porous Si nanostructure can be preserved by impregnating petroleum pitch before high-temperature treatment. A full cell with 80 wt% pitch-derived carbon/nanoporous Si in the anode has been demonstrated with 80% capacity retention after 450 cycles. Low swelling in both particle and electrode levels has also been observed. It is expected that the unique process developed in this work is also applicable for the development of other alloying-type anodes that require preservation of the desired nanostructures during high temperature treatment.

Enhancing the lithium storage performance of α-Ni(OH)2 with Zn2+ doping

Flower-like Zn 2+ doped α -Ni(OH) 2 samples were synthesized via a facile hydrothermal method. The Zn 2+ doped α -Ni(OH) 2 sample with Zn 2+ /Ni 2+ molar ratio of 45% (45-ZN) exhibits much-improved cycling stability, high-rate capability, and electrochemical reaction kinetics due to the unique flower-like nanostructures and the synergetic effect between Ni 2+ and Zn 2+ . • Zn 2+ doped α -Ni(OH) 2 was prepared by homogeneous precipitation method. • The Zn 2+ doped α -Ni(OH) 2 was evaluated as an anode material for LIBs. • Zn 2+ doping effectively enhanced the cycling stability and high-rate capability. • The Zn 2+ doped α -Ni(OH) 2 exhibited an obvious pseudocapacitive behavior. To enhance the lithium storage performance of α -Ni(OH) 2 , different amount of Zn 2+ (with Zn 2+ /Ni 2+ molar ratio of 0 %, 15 %, 30 %, 45 %, and 60 %, respectively) was introduced into the lattice of α -Ni(OH) 2 samples by a facile hydrothermal method. The influence of Zn 2+ doping on the microstructure and lithium storage performance of α -Ni(OH) 2 was investigated in detail. The results demonstrate that with the increase of Zn 2+ /Ni 2+ molar ratio, the microstructure of the as-prepared samples transforms from an urchin-like morphology to flower-like morphology, accompanied by the phase structure transforming from pure-phase α -Ni(OH) 2 to mixed-phase α -Ni(OH) 2 /Zn(OH) 2 . Electrochemical characterizations reveal that Zn 2+ doping can effectively enhance the lithium storage performance of α -Ni(OH) 2 . In particular, the Zn 2+ doped α -Ni(OH) 2 with Zn 2+ /Ni 2+ molar ratio of 45 % (45-ZN) exhibits superior cycling stability (maintaining a reversible capacity of 713 mA h g −1 at a current density of 0.5 A/g after 50 cycles), outstanding high-rate capability (delivering a high specific capacity of 485 mA h g −1 at 2.0 A/g), and fast electrochemical reaction kinetics. GITT analysis demonstrates that the lithium ions diffusion coefficient of the 45-ZN varies in the range of 10 −10 –10 −12 cm 2 s −1 , higher than that (10 −10 –10 −13 cm 2 s −1 ) of pure α -Ni(OH) 2 . In addition, the 45-ZN sample presents an obvious pseudocapacitance behavior during the discharging/charging process. The synergetic effect between Ni 2+ and Zn 2+ can account for the improved electrochemical performance of the Zn 2+ doped α -Ni(OH) 2 . The work provides clues for the preparation and performance optimization of α -Ni(OH) 2 as an anode material for lithium-ion batteries from the aspect of metal ions doping.

In-situ embedding Co9S8 nanoparticles in polyaniline-based carbon nanotubes for enhanced lithium storage

In this work, Co 9 S 8 nanoparticles embedded polyaniline-based carbon nanotubes (Co 9 S 8 /C nanotubes) have been prepared vis polymerization of aniline, rotary evaporation and further calcination, in which the melamine tubes from protonated melamine under the induction of NO 3 - , serve as templates for the preparation of PAIN tubes by polymerization. After calcination, PANI-based carbon nanotubes provide a good carrier for Co 9 S 8 nanoparticles. The N doping in the carbon nanotubes and unique structure endow Co 9 S 8 /C nanotubes with good electronic and ionic conductivity. As a result, Co 9 S 8 /C nanotubes show favorable rate capability (645 mA h g −1 at 0.2 A g −1 and 524 mA h g −1 at 0.5 A g −1 ) and superior cycling performance at 1.0 A g −1 for 500 cycles, making them promising anode candidate for high-performance lithium-ion batteries. • Nano Co 9 S 8 embedded PANI-based carbon nanotubes are prepared by in-situ strategy. • Melamine tubes act as sacrificial template for the synthesis of Co 9 S 8 /C nanotubes. • Co 9 S 8 /C nanotubes show favorable performances as anode materials for LIBs.

One-pot synthesis of N-doped carbon nanosheets from Victorian brown coal with enhanced lithium storage

We report a novel one-pot synthesis method of N-doped porous carbon nanosheets (NCNS) from Victorian brown coal (VBC), which puts forward a sustainable alternative method of utilizing these vast and low-cost resources. VBC and urea were used as the carbon and nitrogen sources in the synthesis process. Benefiting from the porous nanosheet structure and doped N atoms in the carbon matrix, the prepared NCNS at a VBC:urea ratio of 1:3 delivered a promising specific capacity of 604.7 mAh/g at the current density of 50 mA/g. After the cycling performance under 1000 cycles at 1000 mA/g, the reversible capacity remained at 303.6 mAh/g (capacity retention of 97.43%), suggesting a superior stability. Various analytical techniques were used to establish the formation mechanism of NCNS in the presence of urea as well as the charge storage behavior and mechanism in the developed NCNS. The proposed process has great potential for the efficient conversion of VBC into high-performance carbon anode materials for LIBs.