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Despite the essential role of ethylene carbonate (EC) in solid electrolyte interphase (SEI) formation, the high Li

1 M LiFSI in cyclopentyl methyl ether is shown as a novel electrolyte with a unique solvation structure to form a thin robust multilayer solid electrolyte interface with an inorganic LiF-rich inner layer. Aggregates and contact ion pairs are actively formed in the solvation shell and reduced on the graphite anode during lithiation. This EC-free electrolyte provides 86.9% initial efficiency, and 355 mA h g

Surface modification is one of the impressive and widely used technique to improve the electrochemical performance of sodium-ion batteries by modifying the electrode-electrolyte interface. Herein, we used the atomic layer deposition (ALD) to modify the surface of P2-Na0.5Mn0.5Co0.5O2 by sub-monolayer Al2O3 coating on the prefabricated electrodes. Phase purity is confirmed using various structural and morphological studies. The pristine electrode delivered an initial discharge capacity of 154 mAh g−1 at 0.5C, and inferior rate performance of 23 mAh g−1 at 40C rate. On the other hand, the interfacial modified cathode with 5 cycles of ALD coating delivers a high capacity of 174 and 45 mAh g−1 at 0.5C and 40C rate, respectively. The Co2+/3+ redox couple is utilized for the faradaic process with high reversibility along with suppressed P2-O2 phase transition. The presence of the Al2O3 layer acts as an artificial cathode electrolyte interface by suppressing the electrolyte oxidation at higher cutoff potentials. This is clearly validated by the reduced charge transfer resistance of surface modified electrodes after cycling at various current rates. Even at an elevated temperature condition (50 °C), interfacial layer significantly improves the safety of the cell and ensures the stability of the cathode.

Developing novel cathode materials with a high energy density and long cycling stability is necessary for Na-ion batteries and Na-ion hybrid capacitors (NICs). Despite their high energy density, structural flexibility, and ease of synthesis, P-type Na layered oxides cannot be utilized in energy-storage applications owing to their severe capacity fading. In this regard, we report a novel composite layered-tunnel Na

Herein, we demonstrate a new non-aqueous potassium-ion hybrid capacitor (KIC) using novel P3-K 0.45 Mn 0.5 Co 0.5 O 2 and commercial activated carbon (CAC) as the cathode and anode, respectively. A simple sol�gel method is used to synthesize the P3-K 0.45 Mn 0.5 Co 0.5 O 2 cathode nanoplatelets. The structural and morphological studies are performed using various characterization techniques, and their electrochemical performances are studied in half-cell configurations against metallic K. The P3-K 0.45 Mn 0.5 Co 0.5 O 2 nanoplatelets can reversibly host K + ions delivering a high capacity of 140 mAh g �1 in the wide voltage window of 1.2�3.9 V. Exhibiting smooth voltage profiles, it offers reasonable rate capability and cyclability, retaining over 80 capacity after 50 cycles. Involving a two-phase (P3�O3) redox mechanism, P3-K 0.45 Mn 0.5 Co 0.5 O 2 forms robust cathode material for potassium-ion batteries. With Activated Carbon, the capacitor could provide very high energy and power densities of 43 Wh kg �1 and 30 kW kg �1 , respectively, in the voltage range of 0�3.0 V. Even at a 3-s charge�discharge rate (10 A g �1 ), an energy density of 14.5 Wh kg �1 could be retained (corresponding to a power of 15 kW kg �1 ). Also it could retain 88 of its energy density with a substantially high stability up to 30,000 cycles at 10 A g �1 . © 2019 Elsevier B.V.

For the fabrication of aqueous Li-ion hybrid supercapacitor, carbon coated LiCo1/3Ni1/3Mn1/3O2 (or LiCo1/3Ni1/3Mn1/3O2@C composite) is synthesized by polymeric precursor method with subsequent thermal decomposition procedures for carbon coating. Graphene like porous carbon is obtained by chemical activation from the biomass of Agave Americana. The XRD analysis reveals that LiCo1/3Ni1/3Mn1/3O2 is having a hexagonal layered structure and activated carbon exists in both amorphous and graphitic nature. The TEM image infers that LiCo1/3Ni1/3Mn1/3O2 particles having the non-uniform shape with sub-micron size and the LiCo1/3Ni1/3Mn1/3O2 particles are embedded into amorphous carbon cloud in the composite. The activated carbon shows the specific surface area of 1219 m2 g−1. Finally, the fabricated aqueous LiCo1/3Ni1/3Mn1/3O2@C‖AC hybrid supercapacitor delivers the specific capacitance of 56 F g−1 with good capacity retention even after 5000 cycles.

In addition to their optoelectronic applications, Zn-based oxides and sulfides have also been widely studied as electrode materials in Li-ion batteries owing to their high theoretical capacity. However, both the materials suffer from a drastic loss in capacity due to their poor conductivity and electrochemical instability. A very efficient and carefully controlled combination of these two may address these limitations. In this work, thin films of zinc oxysulfide (ZnOS) with an O/(O + S) ratio of ∼0.7 were deposited using a combination of oxide and sulfide atomic layer deposition (ALD) cycles; they were then tested as anodes in Li-ion batteries. The material was grown directly on a stainless steel substrate (SS), characterized extensively using several ex situ characterization tools, and then used as an anode with no binder or conductive additives. Cyclic voltammetry measurements were used to confirm the reversible conversion of ZnOS in addition to the well-known alloying–dealloying Li–Zn reaction. The material loading was further optimized by varying the number of ALD supercycles to attain the maximum stable cycling performance. The highest stable capacities of 632.9 and 510.3 mA h g−1 were achieved at current densities of 0.1 and 1 A g−1 (∼4 and 40 μA cm−2), respectively, for a ZnOS film with an optimum thickness of ∼75 nm. The optimized ZnOS anode exhibited superior electrochemical performance in comparison to the equivalent pristine ZnO and ZnS anodes. Finally, the post-cycling analysis of the binder-free ALD grown ZnOS anodes demonstrated excellent adhesion to the SS substrate and the high stability of these films upon cycling.

The abundance of sodium resources has recently motivated the investigation of sodium ion batteries (SIBs) as an alternative to commercial lithium ion batteries. However, the low power and low capacity of conventional sodium anodes hinder their practical realization. Although most research has concentrated on the development of high-capacity sodium anodes, anodes with a combination of high power and high capacity have not been widely realized. Herein, we present a simple microwave irradiation technique for obtaining few-layered, ultrathin two-dimensional SnS2 over graphene sheets in a few minutes. SnS2 possesses a large number of active surface sites and exhibits high-capacity, rapid sodium ion storage kinetics induced by quick, nondestructive pseudocapacitance. Enhanced sodium ion storage at a high current density (12 A g–1), accompanied by high reversibility and high stability, was demonstrated. Additionally, a rationally designed sodium ion full cell coupled with SnS2//Na3V2(PO4)3 exhibited exceptional ...

Surface modification is one of the impressive and widely used technique to improve the electrochemical performance of sodium-ion batteries by modifying the electrode-electrolyte interface. Herein, we used the atomic layer deposition (ALD) to modify the surface of P2-Na

We report a novel P2-type Na0.5Ni0.26Cu0.07Mn0.67O2 (NCM) mixed oxide obtained by conventional solid-state method as a prospective cathode for sodium-ion battery (SIB) applications. X-ray diffraction analysis shows that NCM exhibits a hexagonal structure with a P63/mmc (No. 194) space group, in which Na-ions are located in a prismatic environment. The introduction of Cu into the lattice enhances its structural stability, showing a capacity retention of 83% after 100 cycles, which is much better than its native compound. MgO encapsulation was performed to further improve the interfacial kinetics and suppress P2–O2 phase transition. MgO coating significantly improves the electrochemical activity at high cut-off voltages, for instance, highest capacity of 131 mA h g−1 was noted with superior rate performance of 83 and 51 mA h g−1 at 5 and 20C, respectively. As expected, dual modification by Cu-ion doping and MgO coating provides a novel strategy for designing high-rate SIB cathodes.

The abundance of sodium resources has recently motivated the investigation of sodium ion batteries (SIBs) as an alternative to commercial lithium ion batteries. However, the low power and low capacity of conventional sodium anodes hinder their practical realization. Although most research has concentrated on the development of high-capacity sodium anodes, anodes with a combination of high power and high capacity have not been widely realized. Herein, we present a simple microwave irradiation technique for obtaining few-layered, ultrathin two-dimensional SnS

Despite their high specific capacity, sodium layered oxides suffer from severe capacity fading when cycled at higher voltages. This key issue must be addressed in order to develop high-performance cathodes for sodium ion batteries (SIBs). Herein, we present a comprehensive study on the influence of Al doping of Mn sites on the structural and electrochemical properties of a P2–Na0.5Mn0.5–xAlxCo0.5O2 (x = 0, 0.02, or 0.05) cathode for SIBs. Detailed structural, morphological, and electrochemical investigations were carried out using X-ray diffraction, cyclic voltammetry, and galvanostatic charge–discharge measurements, and some new insights are proposed. Rietveld refinement confirmed that Al doping caused TMO6 octahedra (TM = transition metal) shrinkage, resulting in wider interlayer spacing. After optimizing the aluminum concentration, the cathode exhibited remarkable electrochemical performance, with better stability and improved rate performance. Electrochemical impedance spectroscopy (EIS) measurements ...

The ever-increasing requirement of an electrochemical sensor in various paramedical and industrial applications, the recent research is motivated to fabricate a new type of electrode material with unique electrochemical properties for quantitative detection of various target analytes. Recently, the metal diselenides have been interested in a broad range of electrochemical applications due to their interesting electrocatalytic performances. Despite the metal diselenides have been widely focused on hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR), it is not much focused on electrochemical sensor. For the first time, the bimetallic cobalt-iron diselenide nanosphere entrapped functionalized carbon nanofiber (CoFeSe

Electrochemical supercapacitors with high energy density are promising devices due to their simple construction and long-term cycling performance. The development of a supercapacitor based on electrical double-layer charge storage with high energy density that can preserve its cyclability at higher power presents an ongoing challenge. Herein, we provide insights to achieve a high energy density at high power with an ultrahigh stability in an electrical double-layer capacitor (EDLC) system by using carbon from a biomass precursor (cinnamon sticks) in a sodium ion-based organic electrolyte. Herein, we investigated the dependence of EDLC performance on structural, textural, and functional properties of porous carbon engineered by using various activation agents. The results demonstrate that the performance of EDLCs is not only dependent on their textural properties but also on their structural features and surface functionalities, as is evident from the electrochemical studies. The electrochemical results are highly promising and revealed that the porous carbon with poor textural properties has great potential to deliver high capacitance and outstanding stability over 300 000 cycles compared with porous carbon with good textural properties. A very low capacitance degradation of around 0.066 % per 1000 cycles, along with high energy density (≈71 Wh kg-1 ) and high power density, have been achieved. These results offer a new platform for the application of low-surface-area biomass-derived carbons in the design of highly stable high-energy supercapacitors.

Sodium ion batteries have been recently proved to be a cost-effective and promising alternative to lithium-ion batteries for next generation high-energy applications. However, the sluggish intercalation kinetics in batteries greatly forbid the efficient high power operation.[1] Recently, sodium hybrid capacitors (NHCs) emerged as a promising energy storage system to retain high specific energy at high power conditions. Benefiting from the simultaneous sodium intercalation/deintercalation in battery type electrode and anionic adsorption/desorption in capacitor type electrode, a fast kinetics in NHCs have been achieved. However, the poor sodium ion storage in battery electrode along with limited anionic adsorption in commercial electrode diminish the output performance of NHCs. The research on NHCs is still in a nascent stage and requires deep investigation to improve energy retention and cycle stability at high power. The kinetics in both battery and capacitor type electrodes must be synergistically improved to achieve a high energy.[2] In this work, we developed a high performing NHC with metal oxide nanoparticles embedded in graphene network as a battery electrode along with a highly mesoporous carbon derived from bio-mass precursor as a capacitor electrode. The highly favorable architecture in both the electrodes showed an enhanced capability towards ion storage (Shown in Ragone plot). A high energy retention at high power condition along with ultra-high stability have been achieved. The detailed results will be presented and discussed in detail. References [1] J. R. Miller, P. Simon, Science 2008, 321, 651. [2] R. Thangavel, B. Moorthy, D. K. Kim, Y.-S. Lee, Adv. Energy Mater. 2017, 1602654. Figure 1

Correction for ‘Cu-doped P2-Na0.5Ni0.33Mn0.67O2 encapsulated with MgO as a novel high voltage cathode with enhanced Na-storage properties’ by Hari Vignesh Ramasamy et al., J. Mater. Chem. A, 2017, DOI: 10.1039/c6ta10334k.

Since 1990 lithium-ion (Li-ion) batteries have been commercially available and currently remain as the technology of choice for applications where high energy densities are required. Sodium-ion (Na-ion) technology is similar in many ways to Li-ion technology, but is still in its initial stage. Current research trends are mostly based on Na-ion based technology due to several commercial advantages, including lower cost, greater sustainability and improved safety characteristics.1, 2 Among different types of cathode materials available, layered oxides such as NaxMO2 (M = transition metal) have shown great promise in terms of both cost and performance.3,4 According to Delmas et al, these layered oxides are classified into different structures, the most common of which are O3, P2 and P3.5 In these descriptions, the O and P refer to an octahedral (O), or prismatic (P), coordination of the Na-ions, and the number refers to the number of layers in the unit cell. P2-type Na-Ni-Mn-O has been considered as a suitable cathode material for the modern day requirement of high power and energy applications due to their low cost, easy synthesis and high theoretical capacity of greater than 250 mAhg-1. However this material has the serious problem of capacity fading due to structural instability. Cationic substitution and surface coating was an efficient strategy to enhance the electrochemical performance by improving the structural stability and preventing Mn3+ dissolution into electrolyte at higher voltages. In this work a novel P2-type Na0.5Ni0.33Cu0.07Mn0.67O2 was synthesized using the single step conventional solid state method and studied as cathode material for sodium ion batteries. The presence of Cu in the lattice structure enhanced the capacity retention to 83% after 100 cycles along with smooth voltage plateau in the high voltage region as shown in Figure 1. Surface coating with MgO increased the specific capacity of the material in the extended voltage window of 2.0 – 4.5V. The MgO coated material shows a smooth voltage plateau without any phase gliding in the higher voltage as in Figure 2. The capacity retention after 70 cycles is found to be 77.6% with enhanced performance. Hence the MgO coated Na0.5Ni0.26Cu0.07Mn0.67O2is studied as a novel cathode for room temperature Na-ion batteries. References: [1] V. Palomares, P. Serras, I. Villaluenga, K.B. Hueso, J. Carretero-Gonz, T. Rojo, Energy Environ. Sci. 5, 2012, 5884. [2] J. Barker, M.Y. Saidi, J. Swoyer, Electrochem. Solid St. 6, 2003, A1. [3] S.W. Kim, D.H. Seo, X. Ma, G. Ceder, K. Kang, Adv. Energy Mater. 2, 2012, 710. [4] M. Slater, D. Kim, E. Lee, C.S. Johnson, Adv. Func. Mater. 23, 2013, 947. [5] C. Delmas, C. Fouassier, P. Hagenmuller, Physica B+C , 99, 1980, 81. Figure 1(a). Cycle stability of Na0.5Ni0.26Cu0.07Mn0.66O2 at 0.25C from 2.0 - 4.25V. ( Inset figure shows the XRD pattern and unit cell diagram of metal substituted sample). (b) Cyclic stability of MgO coated Na0.5Ni0.26Cu0.07Mn0.66O2 in high voltage of 2-4.5V Figure 1

Sodium ion batteries are emerging candidate for next generation high energy application including electrical vehicles and grid storage.[1] Rather than the similar working principle, the wide availability and low cost of sodium made them a suitable and an interesting candidate for large energy applications. The research for sodium ion batteries is majorly on improving their poor kinetics due to their large ionic radii resulting in low energy and power density.[2]The possible solution could be designing a hybrid capacitor which greatly improves the energy density and power density simultaneously because of their fast kinetics. In this work, we have developed and fabricated a new high performing 3 V sodium hybrid capacitor (NHC) using NASICON structured Na3V2(PO4)3 – (NVP) and a carbon derived from bio resource in an organic electrolyte. Two reactions occurs simultaneously, (i) intecalaction / deintercalation of sodium ions in NVP which brings high energy density, (ii) adsorption/ desorption of anion in the bio carbon giving high power density. An energy density of 118 Wh kg−1 has been achieved at a specific power of 95 W kg−1, retaining 60 Wh kg−1 of energy at high specific power of 850 W kg−1. A superior and an extremly outstanding stability of 95% is achieved after 10,000 cycles. The obtained results are one of the highest ever reported and it outperforms the present lithium hybrid capacitor by all means (energy density, power density, stability). The results will be presented and discussed in detail. References: 1) N. Yabuuchi,M. Kajiyama, J. Iwatate, H. Nishikawa, S. Hitomi, R. Okuyama, R. Usui, Y. Yamada, S. Komaba, Nat.Mater. 2012, 11, 512. 2) V. Etacheri, R. Marom, R. Elazari, G. Salitra, D. Aurbach, Energy Environ. Sci. 2011, 4, 3243. Figure 1