High-Performance Asymmetric Supercapacitor Designed with a Novel NiSe@MoSe₂ Nanosheet Array and Nitrogen-Doped Carbon Nanosheet

Abstract

Herein, a novel asymmetric supercapacitor (ASC) with high energy density is fabricated based on the NiSe@MoSe2 nanosheet arrays and the nitrogen-doped pomelo mesocarps-based carbon nanosheet (N-PMCN) as a positive electrode and a negative electrode, respectively. The novel NiSe@MoSe2 nanosheet arrays are designed and prepared by a facile one-step hydrothermal growth method from nickel foam as a nickel precursor and nucleation framework. The N-PMCN is prepared using simultaneous CaCl2 activation and urea nitrogen-doped processes from thepomelo mesocarps as a biomass-based carbon precursor. Because of the unique nanosheet array architecture of NiSe@MoSe2 and interconnected sheet-like porous morphology with high nitrogen content (∼9 wt %) of N-PMCN, they exhibit a maximum specific capacity of 128.2 mAh g–1 and high specific capacitance of 223 F g–1 at a current density of 1 A g–1. Moreover, the assembled novel NiSe@MoSe2//N-PMCN ASC device with a maximum operating voltage of 1.65 V has demonstrated a high energy density of 32.6 Wh kg–1 at a power density of 415 W kg–1 and outstanding cycling stability with 91.4% capacitance retention after 5000 cycles in aqueous electrolyte.

Ni(OH)2 Nanoflakes Supported on 3D Ni3Se2 Nanowire Array as Highly Efficient Electrodes for Asymmetric Supercapacitor and Ni/MH Battery

“…Ni 3 Se 2 @Ni(OH) 2 //AC exhibited an energy density of 59.47 Wh kg −1 at a power density of 100.54 W kg −1 (Figure S9, Supporting Information). These parameters are much better than many ASCs reported elsewhere which contained selenidesor nickel hydroxide-based electrodes as presented in Figure S9 of the Supporting Information, such as Ni 0.85 Se@MoSe 2 //AC with 25.5 Wh kg −1 at a power density of 420 W kg −1 , [42] NiSe@ MoSe 2 //AC (27.5 Wh kg −1 at a power density of 400 W kg −1 ), [43] Ni 3 Se 2 NSs@CF//AC (32.8 Wh kg −1 at a power density of 677.03 W kg −1 ), [24] Ni 0.67 Co 0.33 Se//RGO (36.7 Wh kg −1 at a power density of 750 W kg −1 ), [44] β-Ni(OH) 2 //AC (36.2 Wh kg −1 at a power density of 100.6 W kg −1 ), [45] and Co 3 O 4 @Ni(OH) 2 (41.83 Wh kg −1 at a power density of 33.46 W kg −1 ). [46] A total volume of the Ni 3 Se 2 @Ni(OH) 2 //AC cell was measured to be 0.076 cm 3 , and its volumetric energy density was 47.26 Wh L −1 at a power density of 52.33 W L −1 (Figure 5c), much higher parameters than those of previously reported materials, such as MnO 2 /RGO/CF//GH/CW (0.9 mWh cm −3 ), [47] asymmetric C-SC (1.8 mWh cm −3 at a power density of 50 mW cm −3 ), [48] MnO 2 /graphene//VOS@C (0.5 mWh cm −3 at a power density of 0.05 W cm −3 ).…”

“…Ni 3 Se 2 @Ni(OH) 2 //AC exhibited an energy density of 59.47 Wh kg −1 at a power density of 100.54 W kg −1 (Figure S9, Supporting Information). These parameters are much better than many ASCs reported elsewhere which contained selenides‐ or nickel hydroxide‐based electrodes as presented in Figure S9 of the Supporting Information, such as Ni 0.85 Se@MoSe 2 //AC with 25.5 Wh kg −1 at a power density of 420 W kg −1 , NiSe@MoSe 2 //AC (27.5 Wh kg −1 at a power density of 400 W kg −1 ), Ni 3 Se 2 NSs@CF//AC (32.8 Wh kg −1 at a power density of 677.03 W kg −1 ), Ni 0.67 Co 0.33 Se//RGO (36.7 Wh kg −1 at a power density of 750 W kg −1 ), β‐Ni(OH) 2 //AC (36.2 Wh kg −1 at a power density of 100.6 W kg −1 ), and Co 3 O 4 @Ni(OH) 2 (41.83 Wh kg −1 at a power density of 33.46 W kg −1 ) …”

MoS2/NiS Yolk–Shell Microsphere‐Based Electrodes for Overall Water Splitting and Asymmetric Supercapacitor

“…The advanced Ragone plots of MoS 2 /NiS//AC ASC are shown in Figure h. Impressively, the maximum specific energy density of 31 Wh kg −1 is delivered by the fabricated ASC device at a power density of 155.7 W kg −1 , and an energy density of 9.8 Wh kg −1 can be maintained even at a power density as high as of 1523.9 W kg −1 , surpassing many previously reported ASC systems, such as NiSe@MoSe 2 //AC, CNT/Ni(OH) 2 //AC, NiCo 2 S 4 //AC, MnS//EDAC, NiCo 2 S 4 //porous carbon, α‐Co(OH) 2 /Co 3 O 4 //AC, NiCo 2 O 4 ‐rGO//AC, β‐Ni(OH) 2 //AC . Such prominent performance with high specific capacitance and outstanding cycle stability of the as‐fabricated MoS 2 /NiS//AC ASC device could be ascribed to the unique yolk–shell hollow structure.…”

Ultrahigh‐Working‐Frequency Embedded Supercapacitors with 1T Phase MoSe2 Nanosheets for System‐in‐Package Application

“…Therefore, we can expect an excellent stability for our devices. As for the slightly increase in capacitance, one possible reason is that an improved wetting of the electrolyte on the nanosheets electrodes could be achieved after long‐time immersing . Another factor influencing the capacitance is the morphology change after cycling.…”