The Semicoherent Interface and Vacancy Engineering for Constructing Ni(Co)Se₂@Co(Ni)Se₂ Heterojunction as Ultrahigh‐Rate Battery‐Type Supercapacitor Cathode

Abstract

Restricted rate capability is the key bottleneck for the large‐scale energy storage of battery‐type supercapacitor cathode due to its sluggish reaction kinetics. Herein, Ni(Co)Se2@Co(Ni)Se2 semicoherent heterojunctions with rich Se vacancies (Vr‐Ni(Co)Se2@Co(Ni)Se2) as cathode are first constructed. Such a vacancy and heterointerface manipulation can not only essentially regulate the electronic structure and enhance ions adsorption capability, but also rationalize the chemical affinities of OH– ions in diffusion pathway revealed by systematic characterization analysis and first‐principle calculations. The as‐prepared cathode delivers large specific capacity of 264.5 mAh g–1 at 1 A g–1 and excellent cycle stability. Surprisingly, it presents ultrahigh rate with the retention of 159.7 mAh g–1 even at 250 A g–1. Moreover, the single phase transition mechanism of the cathode is elucidated systematically using series of ex situ techniques. In addition, contributed by the unique cathode and the self‐synthesized N/S co‐doped corncob‐derived porous carbon (N/S‐BPC, 316.1 F g–1 at 1 A g–1) anode, a high‐performance hybrid supercapacitor (HSC) is developed, which shows the energy density of 68.1 Wh kg–1 at 0.75 kW kg–1 and a superior cycle performance. The findings highlight a coordination strategy for the rational design of ultrahigh‐rate battery‐type HSC cathode, greatly pushing their commercial application processes.

Novel core–shell nanoclusters composed of multiple nickel–cobalt-oxyselenide nanowires wrapped with NiCo-LDH nanosheets for high energy density supercapacitors

“…When the power density is 800 W kg −1 , the energy density of the HSC reaches 89.7 W h kg −1 and when the power density is 1600 W kg −1 , the energy density is 84.6 W h kg −1 . The energy and power density values of this HSC device are better than the previously reported HSC values, such as (Ni,Co)Se 2 /NiCo-LDH//PC (39 W h kg −1 at 1650 W kg −1 ), 7 CNTs@NiCo-LDH//ZIF-8 (37.38 W h kg −1 at 800 W kg −1 ), 29 ZnO/C@(Ni,Co)Se 2 //AC (65.67 W h kg −1 at 800 W kg −1 ), 46 (Ni,Co)Se 2 @rGO//AC (52.6 W h kg −1 at 803.4 W kg −1 ), 47 P-(Ni,Co)Se 2 NAs//ZC (45 W h kg −1 at 446.3 W kg −1 ), 48 CC@NiCo-LDH/Co 9 S 8 (38 W h kg −1 at 800 W kg −1 ), 49 Co(OH) 2 /CoSe 2 //CNTs (68.7 W h kg −1 at 189 W kg −1 ), 9 CC/NiCoP @ NiCo-LDH//AC (57 W h kg −1 at 850 W kg −1 ), 50 and PANI@NiSe 2 //AC (38.3 W h kg −1 at 308 W kg −1 ). 51 To demonstrate the application potential of the device, we used solid-state HSCs in series.…”

“…Many effective strategies, such as introducing defect engineering, 7 designing composite structures, 8 and non-metal doping, 9 can enhance the conductivity of TMSes. Based on the synergistic effect of the composite structures, the redox reactions of multiple components can promote effective charge transfer and conductivity enhancement.…”

NiCo layered double hydroxide nanocages for high-performance asymmetric supercapacitors

“…The values show that the kinetics of NiCo-LDH-1 are controlled by both capacity and diffusion processes. 54…”

“…The values show that the kinetics of NiCo-LDH-1 are controlled by both capacity and diffusion processes. 54 To further explore the energy storage mechanism of the NiCo-LDH-1 electrode, the capacitive contribution (h 1 ν) and the diffusion control contribution (h 2 ν 1/2 ) are discussed in detail. The relative expression is as follows:…”

Metal–organic frameworks and their derivatives for metal-ion (Li, Na, K and Zn) hybrid capacitors

“…To date, heterostructures have been reported for SCs and MIBs. 249–251 MIHCs are hybrid energy storage systems based on SCs and MIBs. Developing anodes with enhanced kinetics to match the fast kinetics of cathodes or increasing the capacity of cathodes will improve the overall performance of MIHC devices.…”