P2- a2=3Mn2=3M1=3O2 (M = Fe, Co, Ni) cathode materials in localized high concentration electrolyte for the long-cycling performance of sodium-ion batteries (original) (raw)
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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
Layered P2-Na2/3Co1/2Ti1/2O2 as a high-performance cathode material for sodium-ion batteries
Journal of Power Sources, 2017
A positive electrode material based on Co and Ti for Na-ion batteries was prepared. Na 2/3 Co 1/2 Ti 1/2 O 2 crystallizes in P2type structure with P6 3 /mmc space group. A specific discharge capacity of 100 mAh g À1 was obtained. Na 2/3 Co 1/2 Ti 1/2 O 2 shows better stability than Na 2/3 CoO 2 (Cap. Ret. 98%). Ex-situ XRD confirms the structural stability of the studied material upon cycling.
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...
Layered Na[Ni1/3Fe1/3Mn1/3]O2 cathodes for Na-ion battery application
Electrochemistry Communications, 2012
Na-ion batteries were tested with layered Na(Ni 1/3 Fe 1/3 Mn 1/3)O 2 cathodes and carbon anodes in a sodiumsalt containing organic ester carbonate electrolyte. Layered single phase Na(Ni 1/3 Fe 1/3 Mn 1/3)O 2 was synthesized from solid-state reaction using a (Ni 1/3 Fe 1/3 Mn 1/3)C 2 O 4 oxalate precursor and Na 2 CO 3 fired at 850°C with slow-cooling. The Na-ion Na y C/Na 1 − y (Ni 1/3 Fe 1/3 Mn 1/3)O 2 cell had an average voltage of 2.75 V, modest capacity of 100 mA h g − 1 for 150 cycles (1.5-4.0 V), and a capacity of 94 mA h g − 1 at a 1°C rate. X-ray diffraction (XRD) data of extracted cycled electrodes were used to characterize material stability and phases formed upon cycling. It was found that Na 1 − y (Ni 1/3 Fe 1/3 Mn 1/3)O 2 (0 ≤ y ≤ 0.46) maintains a layered structure with good crystallinity over 150 cycles. These results bode well for the development and optimization of rechargeable Na-ion batteries.
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.
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.
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.
Investigating Na-ion battery (SIB) materials is complicated by the absence of a well-performing (reference) electrode material since sodium metal cannot be considered as a quasi-reference electrode. Taking advantage of the activity of both Ni and Mn, herein, the P2-type and Mn-rich Na 0.6 Ni 0.22 Al 0.11 Mn 0.66 O 2 (NAM) material, known to be an excellent positive electrode, is investigated as a negative electrode. To prove NAM stability as both positive and negative electrode, symmetric cells have been assembled without pre-sodiation, which showed a reversible capacity of 73 mA h g À 1 and a remarkable capacity retention of 82.6 % after 500 cycles. The outstanding cycling performance is ascribed to the high stability of the active material at both the highest and lowest Na-ion storage plateaus and the rather limited electrolyte decomposition and solidelectrolyte-interphase (SEI) formation occurring. The long-term stability of NAM at both electrodes enables its use as a "reference" electrode for the investigation of other positive and negative electrode materials for SIBs, resembling the role played by lithium titanate (LTO) and lithium iron phosphate (LFP) in LIBs.
Journal of the American Chemical Society, 2019
While sodium-ion batteries (SIBs) hold great promise for large-scale electric energy storage and low speed electric vehicles, the poor capacity retention of the cathode is one of the bottlenecks in the development of SIBs. Following a strategy of using lithium doping in the transition-metal layer to stabilize the desodiated structure, we have designed and successfully synthesized a novel layered oxide cathode P2− Na 0.66 Li 0.18 Fe 0.12 Mn 0.7 O 2 , which demonstrated a high capacity of 190 mAh g −1 and a remarkably high capacity retention of ∼87% after 80 cycles within a wide voltage range of 1.5−4.5 V. The outstanding stability is attributed to the reversible migration of lithium during cycling and the elimination of the detrimental P2−O2 phase transition, revealed by ex situ and in situ X-ray diffraction and solid-state nuclear magnetic resonance spectroscopy.