Activated-Nitrogen-Doped Graphene-Based Aerogel Composites as Cathode Materials for High Energy Density Lithium-Ion Supercapacitor

Abstract

Lithium-ion supercapacitor (LIC) was fabricated with nanosheet Li 4 Ti 5 O 12 (LTO) as the negative electrode and activated-nitrogendoped graphene-based aerogel composites (a-NGA) as the positive electrode. The structure, morphology, and pore-size distribution of a-NGA was characterized by SEM, TEM, XRD, TGA, XPS, and nitrogen adsorption-desorption method. Electrochemical properties of a-NGA and nanosheet LTO were studied by galvanostatic charge and discharge test. The results indicated that KOH activation effectively modified the porous structure of NGA and improved its specific surface area to achieve better porosity, thereby enhancing the electrochemical properties. The assembled LIC provide a maximum energy density of 70 Wh kg −1 with the power density of 200 W kg −1 in a voltage of 1-3 V, and still retained an energy density of 21 Wh kg −1 at a high power density of 8000 W kg −1 . More significantly, its exhibits good cycling stability with retention of 64% after 10000 cycles at a high current density of 1.5 A g −1 .With the rapid development of sustainable energy, the demand for high-performance electrochemical energy storage services to make efficient use of energy has significantly increased. 1 Among these various energy storage services, lithium-ion batteries (LIB) and electrical double-layer capacitor (EDLC) have gained more attention in the past decades. 2 LIB has high energy density as high as 150-200 Wh kg −1 , and wide-voltage window; however, its power density is relatively low and its cycle life is poor compared with that of EDLC, EDLC exhibits superior power density up to 10 kW kg −1 , fast charge/discharge rates, and long cycle life. 3-5 However, the low energy density of EDLC limits its application. 3 To meet the increasing demand of high energy density, excellent power capability, and long cycle life, a novel hybrid energy storage service, lithium-ion hybrid supercapacitor (LIC), has emerged in 2001 by Amatucci. 6 Briefly, LIC is fabricated from LIB's insertion type materials and EDLC's materials as the negative electrode and positive electrode, respectively. In the charge/discharge process, anode electrode undergoes Li + insertion/desertion reaction and formation of anion double layer at the cathode electrode. By combining two different storage mechanisms of LIB and supercapacitors, the resulting LIC has a higher power density than the LIB and higher energy density than the EDLC and long cycle life. 3,4,7 In general, electrode materials for the electrochemical performance of LIC plays a vital role. 8 In recent years, various electrode materials of LIC that include cathode electrode and anode electrode have been widely published. Since 2001, Amatucci et al. 6 first assembled LIC with activated carbon (AC) as cathode and Li 4 Ti 5 O 12 (LTO) as anode in a non-aqueous electrolyte, in which energy density exceeds 10 Wh kg −1 . Subsequently, amounts of LIC with various electrode materials assembled are reported. Examples of anode electrode materials include LiCrTiO 4 , 9 α-Fe 2 O 3 , 10 prelithiat...

Battery‐Supercapacitor Hybrid Devices: Recent Progress and Future Prospects

“…Benefiting from their high voltage window, theoretically, Li‐ion BSHs based on conventional nonaqueous LIB electrolytes have higher specific energy densities and have aroused enormous research interests. Anode materials such as Ti‐based oxides/compounds (TiO 2 and Li 4 Ti 5 O 12 , etc. ), silicon, Fe 3 O 4 , Nb 2 O 5 , MnO, and intercalated carbon, and cathode materials of LiNi 0.5 Mn 1.5 O 4 , Li 3 V 2 (PO 4 ) 3 , spinel‐LiMn 2 O 4 , Li 2 CoPO 4 F, and their hybrids with various conducting carbon/polymers were investigated for Li‐ion BSHs.…”

Carbon nanofibers (CNFs) supported cobalt- nickel sulfide (CoNi2S4) nanoparticles hybrid anode for high performance lithium ion capacitor

“…5 (PO 4 ) 3 11 , soft carbon 12 , NbN 13 , LiMnBO 3 14 , SnO 2 -C 15 , hard carbon 16 , Nb 2 O 5 @ graphene 17 , TiO 2 -B 18 , etc. Cathodes such as AC, Nb 2 CT x -carbon nanotube 19 , graphene 20 , carbide-derived carbon 21 have been mostly reported. In the aforementioned materials, binders and conductive additives are preferably used.…”

Graphene-Based Cathode Materials for Lithium-Ion Capacitors: A Review

“…Chemical activation is an effective and feasible strategy to produce porous carbon materials with high SSA and large pore volume, which is commonly used in the preparation of commercial AC [ 98 ]. The activation process with KOH as an activation agent is proposed to follow the below reactions [ 99 ]: 6KOH + C → 2K + 3H 2 + 2K 2 CO 3 K 2 CO 3 → K 2 O + CO 2 K 2 CO 3 + 2C → 2K + 3CO K 2 O + C → 2K + CO CO 2 + C → 2CO …”

“…Additionally, N-doped graphene-based porous composites are considered to be promising candidates because of their excellent conductivity and increased capacitance contributed by the electrical double layer and redox reactions [ 118 ]. For example, Fan et al prepared nitrogen-doped graphene-based aerogel composites (NGA) through a sol–gel polymerization of resorcinol, formaldehyde and melamine in the presence of GO, and then activation with KOH [ 98 ]. After carbonization and activation, the obtained NGA showed a loosely packed morphology with a much thinner laminar structure than non-doped samples due to the nitrogen dopant, but they still retained the 3D interconnecting network.…”