A novel sodium hybrid capacitor (NHC) is constructed with an intercalationtype sodium material [carbon coated-Na 3 V 2 (PO 4 ) 3 , C-NVP] and high surface area-activated carbon derived from an eco-friendly resource cinnamon sticks (CDCs) in an organic electrolyte. This novel NHC possesses a combination of high energy and high power density, along with remarkable electrochemical stability. In addition, the C-NVP/CDC system outperforms present, well-established lithium hybrid capacitor systems in all areas, and can thus be added to the list of candidates for future electric vehicles. A careful optimization of mass balance between electrode materials enables the C-NVP/CDC cell to exhibit extraordinary capacitance performance. This novel NHC produces an energy density of 118 Wh kg −1 at a specifi c power of 95 W kg −1 and retains an energy density of 60 Wh kg −1 with high specifi c power of 850 W kg −1 . Furthermore, a discharge capacitance of 53 F g −1 is obtained from the C-NVP/CDC cell at a 1 mA cm −2 current density, along with 95% capacitance retention, even after 10 000 cycles. The sluggish kinetics of the Na ion battery system is successfully overcome by developing a stable, high-performing NHC system.

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.

sodium ion batteries are almost on the verge of commercialization and investigation is still underway to make them widely available for many applications. [10][11][12] Regardless of the change, batteries have failed to satisfy consumer needs in many aspects, especially in terms of next-generation high power applications. [13] The emerging high power devices can neither be powered by state-of-the-art lithium ion batteries nor by low cost sodium ion batteries due to the limited power of such batteries, driven by slow intercalation and deintercalation kinetics. [7,14,15] Although high power electrochemical double layer capacitors (EDLCs) can supply the requisite power, they are inferior to batteries in supplying the necessary energy density. [7,13,[16][17][18][19] Hybrid capacitors (HCs) are a new class of energy storage device that bridge the gap between batteries and EDLCs by delivering high energy at high power without sacrificing the stability, and thereby fulfilling the needs of high power applications. [20,21] HCs operate by the following dual mechanism that occurs simultaneously in two asymmetric electrodes: (i) intercalation/deintercalation of cations delivering high energy and (ii) surface adsorption and desorption of anions supplying high power and stability. Successful intercalation/deintercalation of sodium ions into a suitable electrode paves the way for development of novel, low cost sodium hybrid capacitor systems. [22][23][24] Sodium hybrid capacitors with the right combination of insertion and adsorption electrodes that are kinetically well balanced can retain high energy density and power density with robust durability. [21,[24][25][26] Various intercalation-based electrodes, including layered oxides, sulfates, metal oxides, phosphates, fluorophosphates, hard carbons, red phosphorous, and much more, have been investigated for sodium ion batteries. [27][28][29] In general, sodium insertion electrodes suffer from poor sodium insertion kinetics and poor structural integrity due to the quick transition metal loss and large lattice strain that occur during sodium insertion, thereby restricting their application in hybrid capacitors. However, sodium super ionic conductor (NASICON) structured-NaTi 2 (PO 4 ) 3 (NTP)-insertion materials are considered to be the best choice for hybrid capacitor application due to their high ionic conductivity, quick sodium insertion into their structure due to their ultrafast sodium ion kinetics, and structural stability. [12,[30][31][32] Further, sodium ions can be inserted into NTP materials without compromising their structural integrity, which could further improve their energy retention for longer Hybrid capacitors, especially sodium hybrid capacitors (NHCs), have continued to gain importance and are extensively studied based on their excellent potential to serve as advanced devices for fulfilling high energy and high power requirements at a low cost. To achieve remarkable performance in hybrid capacitors, the two electrodes employed must be superior with enhanced charg...

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 over graphene sheets in a few minutes. SnS 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), accompanied by high reversibility and high stability, was demonstrated. Additionally, a rationally designed sodium ion full cell coupled with SnS//NaV(PO) exhibited exceptional performance with high initial Coulombic efficiency (99%), high capacity, high stability, and a retention of ∼53% of the initial capacity even after the current density was increased by a factor of 140. In addition, a high specific energy of ∼140 Wh kg and an ultrahigh specific power of ∼8.3 kW kg (based on the mass of both the anode and cathode) were observed. Because of its outstanding performance and rapid synthesis, few-layered SnS could be a promising candidate for practical realization of high-power SIBs.

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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-NaMnAlCoO (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 TMO 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 were performed at various states of charge to probe the surface and bulk effects of Al doping. The material presented here exhibits exceptional stability over 100 cycles within a 1.5-4.3 V window and outperforms several other Mn-Co-based cathodes for SIBs. This study presents a facile method for designing structurally stable cathodes for SIBs.

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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 ) 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.