Investigation of sodium content on the electrochemical performance of the Nax(Fe0.35Mn0.35Co0.3)O2 (x = 0.5, 0.6, 0.7, 0.8, 0.9) for sodium-ion batteries (original) (raw)
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Communications Chemistry, 2022
P2-Na2/3[Fe1/2Mn1/2]O2 layered oxide is a promising high energy density cathode material for sodium-ion batteries. However, one of its drawbacks is the poor long-term stability in the operating voltage window of 1.5–4.25 V vs Na+/Na that prevents its commercialization. In this work, additional light is shed on the origin of capacity fading, which has been analyzed using a combination of experimental techniques and theoretical methods. Electrochemical impedance spectroscopy has been performed on P2-Na2/3[Fe1/2Mn1/2]O2 half-cells operating in two different working voltage windows, one allowing and one preventing the high voltage phase transition occurring in P2-Na2/3[Fe1/2Mn1/2]O2 above 4.0 V vs Na+/Na; so as to unveil the transport properties at different states of charge and correlate them with the existing phases in P2-Na2/3[Fe1/2Mn1/2]O2. Supporting X-ray photoelectron spectroscopy experiments to elucidate the surface properties along with theoretical calculations have concluded t...
J. Mater. Chem. A, 2014
P-type layered oxides are promising cathode materials for sodium-ion batteries and a wide variety of compounds have been investigated so far. Nevertheless, detailed studies on how to link synthesis temperature, structure and electrochemistry are still rare. Herein, we present a study on P-type Na x Ni 0.22 Co 0.11 Mn 0.66 O 2 materials, investigating the influence of synthesis temperature on their structure and electrochemical performance. The change of annealing temperature leads to various materials of different morphologies and either P3-type (700 C), P3/P2-type (750 C) or P2-type (800-900 C) structure. Galvanostatic cycling of P3-type materials revealed high initial capacities but also a high capacity fade per cycle leading to a poor long-term cycling performance. In contrast, pure P2-type Na x Ni 0.22 Co 0.11 Mn 0.66 O 2 , synthesized at 800 C, exhibits lower initial capacities but a stable cycling performance, underlined by a good rate capability, high coulombic efficiencies and high average discharge capacity (117 mA h g À1 ) and discharge voltage (3.30 V vs. Na/Na + ) for 200 cycles. Fig. 1 Schematic illustration of the P2-type and P3-type structures of
Materials, 2021
Herein, we formulated a new O3-type layered Na0.80[Fe0.40Co0.40Ti0.20]O2 (NFCTO) cathode material for sodium-ion batteries (SIBs) using a double-substitution concept of Co in the parent NaFe0.5Co0.5O2, having the general formula Na1-x[Fe0.5–x/2Co0.5–x/2M4+x]O2 (M4+ = tetravalent ions). The NFCTO electrode delivers a first discharge capacity of 108 mAhg−1 with 80% discharge capacity retention after 50 cycles. Notably, the first charge–discharge profile shows asymmetric yet reversible redox reactions. Such asymmetric redox reactions and electrochemical properties of the NFCTO electrode were correlated with the phase transition behavior and charge compensation reaction using synchrotron-based in situ XRD and ex situ X-ray absorption spectroscopy. This study provides an exciting opportunity to explore the interplay between the rich chemistry of Na1–x[Fe0.5–x/2Co0.5–x/2M4+x]O2 and sodium storage properties, which may lead to the development of new cathode materials for SIBs.
Batteries & Supercaps
Mn and Fe based layered oxide materials are potential costeffective cathodes for application in Na-ion batteries. In the present study, Na 2/3 [Mn 3/5 Fe 2/5 ]O 2 is synthesized by a sol-gel method using citric acid as chelating agent, followed by annealing at 900 8C for 12 h. The prepared oxide material is characterized by XRD, SEM and TEM. The electrochemical performance of this cathode material is tested through galvanostatic charge-discharge cycling in the two potential ranges of 2.0-4.2 V and 1.5-4.2 V in Na-ion half-cells using Na foil as the counter and reference electrodes. The material exhibits an initial capacity of about 130 mAh g À1 when cycled at 15 mA g À1 in the potential range of 2.0-4.2 V. The capacity decreases to about 105 mAh g À1 upon cycling retaining about 80 % capacity after 100 cycles. When cycled in the potential range of 1.5-4.2 V, a higher initial capacity of about 150 mAh g À1 is found, which decreases to 90 mAh g À1 , thus retaining about 60 % capacity after 100 cycles. These results indicate that Na 2/ 3 [Mn 3/5 Fe 2/5 ]O 2 can be a potential cathode material for Na-ion batteries, when cycled in the potential range of 2.0-4.2 V. TEM analysis of cycled materials shows the formation of secondary MnÀFe oxide phases along with a change in the oxidation states of the transition metals. The amount of these secondary phases is larger for the sample cycled between 1.5-4.2 V, indicating their crucial role in the ageing mechanism.
Science and Technology Development Journal, 2021
Introduction: Localized high concentration electrolytes (LHCE) have been intensively studied due to their unique properties, especially in suppressing the Na dendrite formation and long-term cycling. Therefore, the low electrochemical performance of the P2-type cathode can be overcome by using LHCE. Methods: P2-type sodium layered oxides Na2=3Mn2=3M1=3O2 (M = Fe, Co, Ni) cathode materials were synthesized via a simple co-precipitation following a supported solid-state reaction. XRD and Rietveld method analyzed the phase composition and lattice parameters. SEM images observed the morphology of materials. The half-cell of three cathode were performed in LHCE consisting of 2.1 M sodium bis(fluorosulfonyl)imide (NaFSI) dissolved in 1,2-dimethoxyethane (DME) and bis(2,2,2-trifluoroethyl) ether (BTFE) (solvent molar ratio 1:2). The galvanostatic charge-discharge, striping-plating, and linear sweep voltage tests were carried out to investigate the electrochemical behaviors. Results: As-pre...
Co-Free P2–Na0.67Mn0.6Fe0.25Al0.15O2 as Promising Cathode Material for Sodium-Ion Batteries
ACS Applied Energy Materials, 2018
P2-Na 0.67 Mn 0.6 Fe 0.25 Al 0.15 O 2 (NaMFA) was developed as cheaper and lesstoxic cathode material for sodium-ion batteries than the Co analogous, P2-Na 0.67 Mn 0.6 Fe 0.25 Co 0.15 O 2 (NaMFC). Despite cobalt being considered to stabilize layered structures upon cycling, NaMFA proved to have not only a higher specific charge 163 mAh•g-1 compared to 141 mAh•g-1 at 0.1C rate, but also a better cycling stability and rate capability than NaMFC. The structural transitions occurring during sodiation/desodiation in the layered frames were characterized by operando X-ray
Batteries, 2016
Sodium-ion batteries (SIBs) are considered a good choice for post-lithium devices. Transition metal sodium pyrophosphates are among the most interesting cathode materials for SIBs. Here we study the electrochemical properties of the system Na 2 Fe 1´x Mn x P 2 O 7 (x = 0, 0.25, 0.5, 0.75, 1). By means of cyclic voltammetry (CV) and galvanostatic experiments, we confirm that pure Fe and Fe-rich compounds are promising for application in sodium batteries, whereas Mn-rich samples are less satisfactory, at least in case of solid-state reaction recipes and standard slurry preparations. Proper carbon coating is likely needed to improve the electrochemical behavior of Mn-rich samples.
DAE SOLID STATE PHYSICS SYMPOSIUM 2019, 2020
Sodium-ion batteries (SIBs) have received significant attention as promising alternative for energy storage applications owing to the large availability and low cost of sodium. In this paper we study the electrochemical behavior of Na 0.7 Co 1-x Nb x O 2 (x = 0 and 0.05 samples), synthesized via solid-state reaction. The Rietveld refinement of x-ray diffraction pattern reveals the hexagonal crystal symmetry with P63/mmc space group. The Na 0.7 Co 0.95 Nb 0.05 O 2 cathode exhibits a specific capacity of about 91 mAhg-1 at a current density of 6mAg-1 , whereas Na 0.7 CoO 2 exhibits comparatively low specific capacity (70 mAhg-1 at a current density of 6mAg-1). The cyclic voltammetry (CV) and electron impedance spectroscopy (EIS) were performed to determine the diffusion coefficient of Na, which found to be in the range of 10 !! − 10 !!" cm 2 s-1 .
Update on Na-based battery materials. A growing research path
Energy & Environmental Science, 2013
This work presents an up-to-date information on Na-based battery materials. On the one hand, it explores the feasibility of two novel energy storage systems: Na-aqueous batteries and Na-O 2 technology. On the other hand, it summarises new advances on non-aqueous Na-ion systems. Although all of them can be placed under the umbrella of Na-based systems, aqueous and oxygen-based batteries are arising technologies with increasing significance in energy storage research, while non-aqueous sodium-ion technology has become one of the most important research lines in this field. These systems meet different requirements of energy storage: Na-aqueous batteries will have a determining role as a low cost and safer technology; Na-O 2 systems can be the key technology to overcome the need for high energy density storage devices; and non-aqueous Na-ion batteries have application in the field of stationary energy storage.
P2-type Na0.67Mn0.65Fe0.2Ni0.15O2 Cathode Material with High-capacity for Sodium-ion Battery
Electrochimica Acta, 2014
Na 0.67 Mn 0.65 Fe 0.35-x Ni x O 2 as a Na storage cathode material was prepared by a sol-gel method. The XRD measurement demonstrated that these samples have a pure P2 phase. The charging/discharging tests exhibit that the Na 0.67 Mn 0.65 Fe 0.35 O 2 electrode has a high initial capacity of 204 mAh g −1 with a slow capacity decay to 136 mAh g −1 , showing higher capacity and considerable cycling performance. When partially substituting Ni for Fe, the Na 0.67 Mn 0.65 Fe 0.2 Ni 0.15 O 2 electrode exhibits higher reversible capacity of 208 mAh g −1 and improved cycling stability with 71% capacity retention over 50 cycles. The greatly improved electrochemical performance for the Na 0.67 Mn 0.65 Fe 0.2 Ni 0.15 O 2 electrode apparently belongs to the contribution of the Ni substitution, which facilitates to improve the electrochemical reversibility of the electrode and alleviate the Jahn-Teller distortion of Mn(III). Therefore, the Ni-substituted Na 0.67 Mn 0.65 Fe 0.2 Ni 0.15 O 2 possibly serves as a promising high capacity and stable cathode material for sodium ion battery applications.