Anode For Na-ion Batteries Research Articles

Exfoliated Graphene Oxide @ Sb2O3 Octahedrons as Alloy-Conversion Anode for High-Performance Na-Ion Batteries with P2-Type Na2/3Ni1/3Mn2/3O2 Cathode

Conversion–alloying–based anodes for sodium–ion batteries (SIBs) have attracted wide interest due to their high energy density and specific capacity. However, it suffers from volume expansion during operation, leading to poor cycling stability. This study introduces a novel carbon matrix, exfoliated graphene oxide (EGO), to alleviate the issues due to volume expansion in the antimony (III) oxide anode for SIBs. Four combinations of Sb2O3 with EGO were explored, and electrochemical performance was compared. An optimized combination (Sb–E1) showed a capacity of ∼100 mAh g–1 at a high current density of 1 A g–1 with good cycling stability. The results show that EGO can effectively buffer the volume expansion and promote fast kinetics. An in–situ electrochemical impedance spectroscopy study revealed that the exceptional charge-transfer resistance varies during the alloying reaction but not during the conversion reaction. The full-cell is fabricated with P2-type layered Na2/3Ni1/3Mn2/3O2 (NNMO) cathode. The Sb–E1/NNMO cell displayed an average operating potential of ∼2.95 V, a high capacity of ∼100 mAh g–1 at a current density of 1 A g–1, and a maximum energy density of ∼100 Wh kg–1.

Facile synthesis of honeycomb-structured biochar with high specific surface and its electrochemical properties as anodes for Na-ion batteries

Facile synthesis of honeycomb-structured biochar with high specific surface and its electrochemical properties as anodes for Na-ion batteries

Pseudocapacitive vs diffusion controlled charge storage in Fe2O3 nanosheet Na-ion battery

Despite of its high potential to be the inexpensive-sustainable replacement to lithium, practical deployment of the sodium ion batteries has been practically hindered by the lack of high performance affordable anodes. The practical use of hematite (Fe2O3) electrodes, a high capacity-earth abundant conversion type Na-ion compatible anode, is practically limited by its substantial volumetric fluctuation upon de/sodiation and constraint electronic transport. Herein, we demonstrate highly reliable pseudocapacitive type Fe2O3 nanosheet anodes for Na-ion batteries produced using a simple but largely industrially viable approach. A unique combination of two dimensional morphology and the optimum crystal perturbations collectively impart an exceptional charge transport characteristics and substancial volume fluctuation buffering. Owing to the distinct 2D morphology and structural features, this nanosheet electrode exhibited dominant pseudocapacitive nature with a maximum contribution of 95 % and delivered good reversible specific capacity and cyclability. Mechanistic investigations with the in-situ Raman analysis revealed insignificant structural changes indicating pseudocapacitive nature of the conversion reaction facilitated by the diffusion independent fast Na-ion mobility in the host lattice. The demonstrated method of producing transition metal oxide electrodes with good commercialization potential may be further exploited to achieve the goal for high performance-sustainable batteries.

Carbonization of Corn Leaf Waste for Na-Ion Storage Application Using Water-Soluble Carboxymethyl Cellulose Binder.

Hard carbon materials are considered to be the most practical anode materials for sodium ion batteries because of the rich availability of their resources and potentially low cost. Here, the conversion of corn leaf biomass, a largely available agricultural waste, into carbonaceous materials for Na-ion storage application is reported. Thermal analysis investigation determines the presence of exothermic events occurring during the thermal treatment of the biomass. Accordingly, various temperatures of 400, 500, and 600 °C are selected to perform carbonization treatment trials, leading to the formation of various biocarbons. The materials obtained are characterized by a combination of methods, including X-ray diffraction, electron microscopy, surface evaluation, Raman spectroscopy, and electrochemical characterizations. The Na-ion storage performances of these materials are investigated using water-soluble carboxymethyl cellulose binder, highlighting the influence of the carbonization temperature on the electrochemical performance of biocarbons. Moreover, the influence of post-mechanochemical treatment on the Na-ion storage performance of biocarbons is studied through kinetic evaluations. It is confirmed that reducing the particle sizes and increasing the carbon purity of biocarbons and the formation of gel polymeric networks would improve the Na-ion storage capacity, as well as the pseudocapacitive contribution to the total current. At a high-current density of 500 mA g-1, a specific Na-ion storage capacity of 134 mAh g-1 is recorded on the biocarbon prepared at 600 °C, followed by ball-milling and washing treatment, exhibiting a reduced charge transfer resistance of 49 Ω and an improved Na-ion diffusion coefficient of 4.8 × 10-19 cm2 s-1. This article proposes a simple and effective technique for the preparation of low-cost biocarbons to be used as the anode of Na-ion batteries.

A facile procedure to improve the performance of food-waste-derived carbons in sodium-ion batteries

The anode of Na-ion batteries under development is dominated by carbon materials, especially hard carbons with poorly organized structures. The production of carbon materials by pyrolysis of food waste is less expensive and more environmentally friendly than from pure organic compounds. In this work, the sulfuric acid pre-treatment of ground coffee grains before carbonization is evaluated as a simple but efficient tool to improve the electrochemical performance of the resulting carbon for the anode of sustainable Na-ion batteries. The carbon product shows a significant reduction in inorganic impurities and a decrease in crystallinity, which results in a reversible capacity close to 33 % higher, enhanced first-cycle efficiency, and better kinetic response than the non-pre-treated materials. Thus, reversible capacities at C/10 increase from ca. 150 mAhg−1 to 200 mAhg−1 after acid treatment, and the capacity of the non-acid-treated samples falls to negligible values at 2C kinetics, in contrast with significant retention of the acid-treated one.

2D-Layer-Structure Bi to Quasi-1D-Structure NiBi3 : Structural Dimensionality Reduction to Superior Sodium and Potassium Ion Storage.

Layer-structured bismuth (Bi) is an attractive anode for Na-ion and K-ion batteries due to its large volumetric capacity and suitable redox potentials. However, the cycling stability and rate capability of the Bi anode are restricted by the large volume expansion and sluggish Na/K-storage kinetics. Herein, a structural dimensionality reduction strategy is proposed and developed by converting2D-layer-structured Bi into a quasi-1D structured NiBi3 with enhanced reaction kinetics and reversibility to realize high-rate and stable cycling performance for Na/K-ion storage. As a proof of concept, the quasi-1D intermetallic NiBi3 with low formation energy, metallic conductivity, and 3D Na/K-ion diffusion pathways delivers outstanding capacity retention of 94.1% (332 mAh g-1 ) after 15000 cycles for Na-ion storage, and high initial coulombic efficiency of 93.4% with improved capacity retention for K-ion storage. Moreover, investigations on the highly reversible Na/K-storage reaction mechanisms and cycling-driven morphology reconstruction further reveal the origins of the high reversibility and the accommodation to volume expansion. The finding of this work provides a new strategy for high-performance anode design by structural dimensionality manipulation and cycling-driven morphology reconstruction.

Monolayer TiSiP as a high-performance anode for Na-ion batteries

Exploring anode materials with overall excellent performance remains a great challenge for rechargeable Na-ion battery technologies. Herein, we have identified that monolayer TiSiP is just such a prospective anode candidate via first-principles calculations. It is showed to be dynamically, thermally, mechanically, and energetically stable, which provides feasibility for experimental realization. The Na diffusion on the its surface is proved to be ultrafast, with a migration energy barrier as low as 73 meV. Electronic structure confirms that the pristine system undergoes a transition from the semiconductor to metal during the whole sodiation process, which is a significant advantage to the electrode conductivity. More excitingly, monolayer TiSiP can accommodate up to double-sided five-layer adatoms, resulting in an ultrahigh theoretical capacity of 1176 mA h g−1 and a low average open-circuit voltage of 0.195 V. Moreover, the maximally sodiated electrode monolayer yields rather small in-plane lattice expansion of only 1.40%, which ensures reversible deformation and excellent cycling stability as further corroborated by structural relaxation and ab initio molecular dynamics simulation. Overall, all of these results point to the potential that monolayer TiSiP can serve as a promising anode candidate for application in high-performance low-cost Na-ion batteries.

Effects of Si, B doping on PC3 monolayer as anode for Na-ion batteries

Effects of Si, B doping on PC3 monolayer as anode for Na-ion batteries

Carbon-coated iron selenide derived from double-framework as an advance anode for Na-ion battery

Owing to the desirable nano-morphology, controllable structure, and ease of preparation, metal–organic frameworks (MOFs) are widely used as the precursors for electrodes in Na-ion battery (NIB). However, MOF structures are prone to fracture and collapse during the reactions. Additionally, MOF-derived electrodes often exhibit a high expansion rate, which negatively impacts the long cyclic capability of NIBs. Herein, we employed a stable covalent-organic framework (COF) as a protective coating for the first time to preserve the MOF structure. A shuttle-like iron selenide (Fe3Se4) coated with N-doped carbon (NC) was synthesized using a simple hydrothermal method, surface coating, and subsequent selenizing process. Due to its large specific surface area and well-developed porosity, the double-framework derived Fe3Se4/NC electrode provides abundant active sites for Na+ storage. The COF and COF-derived NC protect the structure of Fe3Se4/NC during synthesis and cyclic process, respectively. The high conductivity of the NC coating enhances the electron/ion conductivity of Fe3Se4/NC, thereby beneficial the rate performance. As the material anode for NIB, the Fe3Se4/NC electrode exhibits a high initial charging/discharging capacity (425.7/478.4 mAh·g−1 with an initial Coulombic efficiency of 89.0 %), excellent rate performance (333.5 mAh·g−1 at 12 A·g−1), long-durable cycle capability (290.8 mAh·g−1 after 1000 cycles at 8 A·g−1) and fast charging ability (143 s). This work provides a novel strategy of “COF on MOF” to prepare high-performance electrode materials for NIB.

Biopolymer-Based Hard Carbons: Correlations between Properties and Performance as a Na-Ion Battery Anode

Biopolymer-Based Hard Carbons: Correlations between Properties and Performance as a Na-Ion Battery Anode

In-situ growth nickel phosphide/biomass carbon integrated fast-kinetic anode for Na-ion batteries

BackgroundPhosphide has become an efficient electrode material for anode of Na-ion batteries because of its excellent theoretical capacity. However, its lack of conductivity and slow kinetic process were important problems to be solved. The combination of 3D electrode structure design to increase the reaction area and conductive carbon coating strategy will effectively solve such problems. MethodsBiomass hydrolyzed extraction combined with high-temperature carbonization and self-sacrifice phosphating strategy was reported to prepare an integrated Ni2P anode. The apparent activation energy was calculated to reveal the kinetic performance. Galvanostatic intermittent titration technique method and quasi-in-situ XRD were used to analyze the diffusion process of Na+ and the chemical change process of electrode materials during the charge-discharge process, respectively. Significant findingsAs-synthesis integrated anode exhibits excellent surface uniformity and energy storage capacity. At 100 mA.g−1 current density, the initial capacity was close to 500mAh.g−1. and the specific capacity was still higher than 300mAh.g−1 after 100 cycles. The integrated anode also has excellent rate performance, it can still recover 87.5% specific capacity after high current discharge. In addition, during the charging and discharging process, the sodium ion diffusion process and chemical phase transition process of the electrode were systematically revealed.

The effect of Cl encapsulation and hydrogenation process on the performance of ZnO nanocluster as an anode in Na-ion batteries

Density functional theory (DFT) computations are performed for probing the application of a Zn12O12 nanocage as well as its geometrically engineered forms as an anode material in Na-ion batteries (NIBs). The performance of the pure Zn12O12 nanocage was low and its cell voltage (Vcell) was approximately 1.06 V. Therefore, in order to enhance the performance, two methods were projected, namely encapsulation of an anion inside the nanocage and hydrogenation of Zn atoms of the cage. The second method was unsuccessful since it demonstrated a negative Vcell, which was due to the fact that interaction between the atomic Na and the hydrogenated nanocage was stronger than the cationic Na. However, the encapsulation of a chloride inside the Zn12O12 nanocage led to a dramatic increase in the Vcell from 1.06 to 2.96 V, which was greater than the Vcell anticipated for carbon nano-tubes and C24 fullerene.

Two-dimensional dumbbell silicene as a promising anode material for (Li/Na/K)-ion batteries

Rechargeable ion batteries require anode materials with excellent performance, presenting a key challenge for researchers. This paper explores the potential of using two-dimensional dumbbell silicene as an anode material for alkali metal ion batteries through density functional theory (DFT) calculations. Our findings demonstrate that alkali metal ions have negative adsorption energies on dumbbell silicene, and the energy barriers for Li/Na/K ion diffusion are as low as 0.032 eV/0.055 eV/0.21 eV, indicating that metal ions can easily diffuse across the entire surface of dumbbell silicene. Additionally, the average open circuit voltages of dumbbell silicene as anode for Li-ion, Na-ion, and K-ion batteries are 0.42 V, 0.41 V, and 0.60 V, respectively, with corresponding storage capacities of 716 mAh/g, 622 mAh/g, and 716 mAh/g. These results suggest that dumbbell silicene is an ideal anode material for Li-ion, Na-ion, and K-ion batteries, with high capacity, low open circuit voltage, and high ion diffusion kinetics. Moreover, our calculations show that the theoretical capacities obtained using DFT-D2 are higher than those obtained using DFT-D3, providing a valuable reference for subsequent theoretical calculations.

Facile Synthesis of Nickel Phosphide @ N-Doped Carbon Nanorods with Exceptional Cycling Stability as Li-Ion and Na-Ion Battery Anode Material

Nickel phosphide (Ni2P), as an anode material for both lithium- and sodium-ion batteries, offers high theoretical specific and volumetric capacities. However, considerable challenges include its limited rate capability and low cycle stability arising from its volume change and degradation during cycling. To solve these issues, appropriate composite micro/nanoparticle designs can improve conductivity and provide confinement. Herein, we report a simple pyrolysis method to synthesize nitrogen-doped carbon-coated Ni2P nanorod arrays (Ni2P@NC) from nickel foam and an ionic resin as a source of carbon, nitrogen and phosphorus. The N-doped open-ended carbon shells provide Ni2P containment, good electrical conductivity, efficient electrolyte access and the buffering of bulk strain during cycling. Consequently, as a LIB anode material, Ni2P@NC has impressive specific capacity in long-term cycling (630 mAh g−1 for 150 cycles at 0.1 A g−1) and a high rate capability of 170 mAh g−1 for 6000 cycles at 5 A g−1. Similarly, as a SIB anode, Ni2P@NC retains a sizable 288 mAh g−1 over 300 cycles at 0.1 A g−1, and 150 mAh g−1 over 2000 cycles at 2 A g−1. Furthermore, due to a sizable portion of its capacity coinciding with adequately low voltage, the material shows promise for high volumetric energy storage in full-cell format. Lastly, the simple synthesis method has the potential to produce other carbon-coated metal phosphides for electrochemical applications.

Edge Graphitized Oxygen-Rich Carbon Based on Stainless Steel-Assisted High-energy Ball Milling for High-Capacity and Ultrafast Sodium Storage.

Oxygen doping is an effective strategy for constructing high-performance carbon anodes in Na ion batteries; however, current oxygen-doped carbons always exhibit low doping levels and high-defect surfaces, resulting in limited capacity improvement and low initial Coulombic efficiency (ICE). Herein, a stainless steel-assisted high-energy ball milling is exploited to achieve high-level oxygen doping (19.33%) in the carbon framework. The doped oxygen atoms exist dominantly in the form of carbon-oxygen double bonds, supplying sufficient Na storage sites through an addition reaction. More importantly, it is unexpected that the random carbon layers on the surface are reconstructed into a quasi-ordered arrangement by robust mechanical force, which is low-defect and favorable for suppressing the formation of thick solid electrolyte interfaces. As such, the obtained carbon presents a large reversible capacity of 363mAhg-1 with a high ICE up to 83.1%. In addition, owing to the surface-dominated capacity contribution, an ultrafast Na storage is achieved that the capacity remains 139mAhg-1 under a large current density of 100Ag-1 . Such good Na storage performance, especially outstanding rate capability, has rarely been achieved before.

New construction of polypyrrole interphase layers to improve performance stability of NaTi2(PO4)3 anode for aqueous Na-ion batteries

NaTi2(PO4)3 (NTP) as a promising anode material for aqueous sodium-ion batteries has attracted widespread attention. However, the NTP material commonly exhibits significant capacity fade, possibly mainly attributing to the change of the chemical stability of NTP in the aqueous electrolytes. Coating NTP with polypyrrole (PPY) conductive polymers is a promising strategy to solve this problem, but in situ synthesis of the PPY polymer in the presence of the NTP active materials seems not to be easy, reported by the previous work, owing to the inferior adhesion of the synthesized PPY to the NTP surface. Thereby, this work has attempted ex situ synthesis of PPY coatings on the carbon-coated NTP (NTP/C) anode surface in the presence of small amounts of carbon conductive additives and organic binders, and then it shows that synthesized conductive PPY interphase layer can readily adhere to the NTP surface with no visible phase separation through the electrochemical oxidation polymerization under certain potentials in the pyrrole (PY)-containing electrolytes. The corresponding optimized oxidation modification conditions of the anode can be obtained, and the evolution law of the anode interface with the content of the electrolyte additives, the oxidation potential and the oxidation time can be established. Thus, the as-synthesized optimal modified anodes, with the thickness of about 24 μm for the PPY coating, are observed to have fairly large charge/discharge capacity of 228.6 mAh·g−1, high coulombic efficiency (> 95%) and enhanced cycling stability. Furthermore, a schematic for the charge/discharge processes involving possible reaction pathways at the modified anodes with the PPY layers in Na2SO4 aqueous electrolytes has been proposed.

Centrifugally Spun Binder-Free N, S-Doped Ge@PCNF Anodes for Li-Ion and Na-Ion Batteries.

Germanium has a high theoretical capacity as an anode material for sodium-ion batteries. However, germanium suffers from large capacity losses during cycling because of the large volume change and loss of electronic conductivity. A facile way to prepare germanium anodes is critically needed for next-generation electrode materials. Herein, centrifugally spun binder-free N, S-doped germanium@ porous carbon nanofiber (N, S-doped Ge@ PCNFs) anodes first were synthesized using a fast, safe, and scalable centrifugal spinning followed by heat treatment and N, S doping. The morphology and structure of the resultant N, S-doped Ge@ PCNFs were investigated by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray mapping, Raman spectroscopy, and X-ray diffraction, while electrochemical performance of N, S-doped Ge@ PCNFs was studied using galvanostatic charge-discharge tests. The results demonstrate that a nanostructured Ge homogeneously distributed on tubular structured porous carbon nanofibers. Moreover, N, S doping via thiourea treatment is beneficial for lithium- and sodium-ion kinetics. While interconnected PCNFs buffered volume change and provided fast diffusion channels for Li ions and Na ions, N, S-doped PCNFs further improved electronic conductivity and thus led to higher reversible capacity with better cycling performance. When investigated as an anode for lithium-ion and sodium-ion batteries, high reversible capacities of 636 and 443 mAhg-1, respectively, were obtained in 200 cycles with good cycling stability. Centrifugally spun binder-free N, S-doped Ge@ PCNFs delivered a capacity of 300 mAhg-1 at a high current density of 1 A g-1, indicating their great potential as an anode material for high-performance sodium-ion batteries.

Water-Soluble Binders That Improve Electrochemical Sodium-Ion Storage Properties in a NaTi2(PO4)3 Anode

Water-soluble binders are demonstrated to provide significantly better capacity, cycle life stability and rate response for NASICON-type NaTi2(PO4)3 Na-ion battery anodes during reversible sodiation compared to electrodes made using polyvinylidene difluoride-containing slurries. The role of carboxymethyl cellulose (CMC) binders on the physical structure and chemical interfacial reactions with sodium-poor NaTi2(PO4)3 are uncovered using electron microscopy and spectroscopy data and we show that a more stable NASICON NaTi2(PO4)3 structure is found from the desodiation process from compensation of sodium deficiencies in the NaTi2(PO4)3 by extra sodium from the CMC binder. When the binder comprises CMC and a styrene butadiene rubber (SBR) additive, the electrode delivers significantly better voltammetric and galvanostatic electrochemical response with a specific capacity of ∼120 mAh g−1 with capacity retention of 90.5% for 500 cycles at 0.2 C (1 C = 133 mAh g−1), and ∼54 mAh g−1 at 20 C. The durability of the electrode during cycling and the stability of the redox processes ensures a higher capacity, longer cycle life electrode which is important for sustainable materials development for Na-ion technologies.

Anodic Potential and Conversion Chemistry of Anhydrous Iron (II) Oxalate in Na-Ion Batteries

Anhydrous ferrous (II) oxalate (AFO) outperforms its hydrated form when used as an anode material in Li-ion batteries (LIBs). With the increasing interest in Na-ion batteries (NIBs) in mind, we examine the potential of AFO as the anode in NIBs through first principles calculations involving both periodic and non-periodic structures. Our analysis based on periodic (non-periodic) modeling scheme shows that the AFO anode generates a low reaction potential of 1.22 V (1.45 V) in the NIBs, and 1.34 V (1.24 V) in the LIBs, which is much lower than the potential of NIBs with mixed oxalates. The conversion mechanism in the underlying electrochemical process involves the reduction of Fe2+ with the addition of Na or Li. Such conversion electrodes can achieve high capacities through the Fe2+ valence states of iron.

Reduced graphene oxide and carbon nanotube anchored NASICON-type NaTi2(PO4)3 nanocomposite anodes for high-rate performance sodium-ion batteries

NASICON-structured NaTi2(PO4)3 (NTP) anode consist of an open 3D framework is received as a zero-stress anode for Na-ion batteries. Herein, we have reported a novel NTP/GO/CNT nanocomposite anodes, in which NTP particles are engineered with reduce graphene oxide (rGO) and carbon nano tube (CNT) and wrapped using a low-cost facile sol-gel method. NTP-rGO10-CNT10 has been chosen as the optimum electrode after studying the effects of rGO/CNT ratio on the electrochemical performance of NTP. The combine effect of structural integrity, high electronic conductivity and high ionic diffusivity in NTP-rGO10-CNT10 leads to excellent electrochemical performance with regards to specific capacity (124 mA h g−1 at 100 mA g−1), remarkable high-rate cycleability (62.5% capacity retention after 400 cycles at 10 C), and excellent rate capability (87 mA h g−1 at 25C). Using cyclic voltammetry investigation, we have estimated the capacitive and faradaic contributions to the total capacities of the composite electrode at various rate. Besides, carbon incorporated NVOPF obtained by carbo-thermal reduction delivers a specific discharge capacity of 106 mA h g−1 as cathode against sodium. Finally, a Na-ion full-cell with the structure of NTP-rGO10-CNT10│1 M NaClO4 in PC│NVOPF@C has been fabricated. This newly designed full-cell can deliver good electrochemical performance in terms of cycleability and power.