FeCo₂S₄@Ni@graphene Nanocomposites with Rich Defects Induced by Heterointerface Engineering for High-Performance Supercapacitors

Abstract

Rational designing advanced materials with multicomponents and multiscale nanostructures is an important pathway to promote the rapid development and practical application of high-performance supercapacitors. Herein, FeCo2S4@Ni@graphene nanocomposites are prepared through electroless depositionhydrothermal two-step method. In this hybrid structure, the metal nickel as a conductive bridge significantly enhances the charge transport and the structural stability between FeCo2S4 and graphene by encouraging the heterogeneous nucleation of FeCo2S4 on the active Ni@graphene. More importantly, the rich defects are induced into FeCo2S4@Ni@graphene by the interface engineering due to the lattice mismatch at the interface between Ni and FeCo2S4 and partial substitution of Ni for Co or Fe. These defects can provide additional faradic redox reactions and abundant active sites. Benefiting from the synergies of above advantages, the optimized FeCo2S4@Ni@graphene shows a specific capacity of 390.0 mAh g–1 at 1 A g–1. Additionally, the asymmetric supercapacitor based on FeCo2S4@Ni@graphene delivers a high energy density of 65.8 Wh kg–1 at 849 W kg–1, as well as capacitance retention of 89.2% after 6000 cycles at 20 A g–1. This work proposes an effective strategy, which is to regulate the defects in transition-metal compounds through heterointerface engineering to prepare advanced energy-storage materials.

Engineering of Transition Metal Sulfide Nanostructures as Efficient Electrodes for High-Performance Supercapacitors

“…The morphology and composition of TMEMs and the type of the electrolytes are the main factors that determine the SC’s performance . Unlike traditional TMEMs, binary transition metal sulfide (BTMS) electrodes (i.e., NiCo 2 S 4 , CoMoS 4 , CuCo 2 S 4 , MnCo 2 S 4 , and ZnCo 2 S 4 ) possess inherently higher storage capacity, higher electrical conductivity, quicker electron/ion diffusion, better redox properties, and better reversibility with long cycle life. − Additionally, they are endowed with unique physicochemical characteristics, thermal stability, several oxidation states, and richer Faradaic redox reaction properties that enhance the SC’s activity and durability significantly . Furthermore, BTMSs are easily prepared using various high-yielding methods from inexpensive and earth-abundant resources and could be easily combined with other materials or substrates to operate as electrodes for SCs.…”

Defect engineering of electrode materials towards superior reaction kinetics for high-performance supercapacitors

“…FeCo 2 S 4 @Ni@graphene nanocomposites by an interface engineering strategy. 187 The abundant defects, including the vacancies and dislocations were clearly observed in the HRTEM.…”

“…Zheng et al prepared FeCo 2 S 4 @Ni@graphene nanocomposites by an interface engineering strategy. 187 The abundant defects, including the vacancies and dislocations were clearly observed in the HRTEM. The rich defects engineered into the interface regions were due to the lattice mismatch, which could provide more ion diffusion channels to boost ions transfer for enhanced faradaic pseudocapacitance.…”

Interconnected MoS2/FeCo2S4 nanosheet array bifunctional electrocatalysts grown on carbon cloth for efficient overall water splitting

“…4e and f) present more details on the lattice fringes, which match well with the (3 3 1) and (1 1 1) planes of FeCo 2 S 4 and (2 0 0) plane of 1T-MoS 2 . 27,28 The energy-dispersive Xray (EDX) spectrum (Fig. S1, ESI †) reveals that Fe, Co, Mo and S elements coexist in MoS 2 /FeCo 2 S 4 /CC and their mass ratio is 0.135 : 0.562 : 0.614 : 1.…”