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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