Zn–Co Sulfide Microflowers Anchored on Three‐Dimensional Graphene: A High‐Capacitance and Long‐Cycle‐Life Electrode for Asymmetric Supercapacitors

Abstract

Zinc-cobalt double-metal sulfides (ZCS) as Faradic electrode materials with high energy density have great potential fors upercapacitors, but their poor transfer efficiency for electrons and ions hinders their electrochemical response.H erein, ZnCo 2 (CO 3 ) 1.5 (OH) 3 @ZCS microflower hybrid arrays consisting of thin nanolayer petals were anchored on three-dimensional graphene (ZnCo 2 (CO 3 ) 1.5 (OH) 3 @ZCS/3DG) by as imple hydrothermal method and additional ion-exchangep rocess. AZ nCo 2 (CO 3 ) 1.5 (OH) 3 @ZCS/3DG electrode delivered high capacitance (2228 Fg À1 at 1Ag À1 )a nd long cycling life (85.7 %r etention after 17 000 cycles), which are ascribedt ot he multicomponents tructural design. The 3DGconductive substrate improves the electron-transfer dynamics of the electrode material. Meanwhile, the microflowers consisting of thin nanolayer petals could not only provide many actives ites for ions to improve thec apacitance, but also alleviate the volumee xpansion to ensure the structural stability. Furthermore,a na ll-solid-state asymmetric supercapacitor based on aZ nCo 2 (CO 3 ) 1.5 (OH) 3 @ZCS/3DG electrode achieved ah igh energy density of 27 Whkg À1 at 528.3 Wkg À1 ande xhibits exceptional cyclic stability for 23 000 cycles. Its ability to light ab lue LED for 9min verified the feasibility of its applicationf or energy storagedevices.[a] Q. Figure 3. a) XRD pattern of ZnCo 2 (CO 3 ) 1.5 (OH) 3 @ZCS powder,b)Raman spectrum of ZnCo 2 (CO 3 ) 1.5 (OH) 3 @ZCS/3DG,c )XPS full spectrum of ZnCo 2 (CO 3 ) 1.5 (OH) 3 @ZCS/3DG,d -f) Zn 2p, Co 2p, and S2 ph igh-resolution XPS spectra, respectively.

In Situ Construction of a Heterostructured Zn–Mo–Ni–O–S Hollow Microflower for High-Performance Hybrid Supercapacitors

“…Notably, the device delivers a maximum energy density of 60.8 Wh kg –1 at a power density of 750.2 W kg –1 and remains to have an energy density of 35.1 Wh kg –1 when the power density is 3737.4 W kg –1 . The achieved energy density of our ASC device is superior to previous works, such as Zn–Ni–P–S//AC (29.01 W h kg –1 at 275.54 W kg –1 ), Zn–Ni–Co–O//AC (35.6 Wh kg –1 at 187.6 W kg –1 ), Ni 1– x Zn x S//AC-G (38.9 Wh kg –1 at 327 W kg –1 ), ZnCo 2 (CO 3 ) 1.5 (OH) 3 @ZCS/3DG//AC (27 Wh kg –1 at 528 W kg –1 ), ZnS/Ni 3 S 2 //PrGO (30.6 Wh kg –1 at 880 W kg –1 ), Zn–Co–O//AC (33.98 Wh kg –1 at 800 W kg –1 ), and Ni–Zn–Fe LDH//AC (14.9 Wh kg –1 at 1077.6 W kg –1 ), respectively. Therefore, the superior quality of the binder-free Zn–Mo–Ni–O–S HMF as a positive electrode for the HSC device could be a great potential equipment toward practical energy transformation and storage application.…”

“…When the reaction time is 8 h (Zn–Mo–O–8 SMF), the nanosheets are aggregated together with increased thickness (Figure S4h,i). The Zn–Mo–O–6 SMF possesses well-ordered arranged nanosheets and rich channels (Figure S4e,f), which are favorable for ion diffusion and charge transfer and provide an appropriate template for the sulfurization process compared with the Zn–Mo–O–4 SMF and Zn–Mo–O–8 SMF . The XRD pattern of the Zn–Mo–O SMF precursor with different reaction temperatures is shown in Figure S1a.…”

“…Taking the PVA/KOH hydrogel as the solid electrolyte, the Zn−Mo−Ni−O−S HMF and AC were used as the positive and negative electrode to assemble the all-solid-state SC device. In the picture inset in Figure 6a 51 Ni 1−x Zn x S//AC-G (38.9 Wh kg −1 at 327 W kg −1 ), 52 ZnCo 2 (CO 3 ) 1.5 (OH) 3 @ZCS/3DG//AC (27 Wh kg −1 at 528 W kg −1 ), 27 ZnS/Ni 3 S 2 //PrGO (30.6 Wh kg −1 at 880 W kg −1 ), 53 Zn−Co−O//AC (33.98 Wh kg −1 at 800 W kg −1 ), 54 and Ni−Zn−Fe LDH//AC (14.9 Wh kg −1 at 1077.6 W kg −1 ), 55 respectively. Therefore, the superior quality of the binder-free Zn−Mo−Ni−O−S HMF as a positive electrode for the HSC device could be a great potential equipment toward practical energy transformation and storage application.…”

ZIF-Derived Porous CoNi2S4 on Intercrosslinked Polypyrrole Tubes for High-Performance Asymmetric Supercapacitors

“…Increasingly severe environmental problems and energy crises have urged more research toward the development of cost-effective and sustainable energy storage technologies . As a new type of cost-effective and efficient energy storage device, supercapacitors (SCs) have the advantages of high power density, rapid charge storage capability, and impressive cycling stability. , Therefore, it is a highly desirable high-power source for portable electronic devices. However, compared with rechargeable batteries, the energy density of SCs is relatively low, which hinders its further applications.…”

Non-Enzymatic Glucose Sensing Based on Incorporation of Carbon Nanotube into Zn-Co-S Ball-in-Ball Hollow Sphere

“…Recently, controlling the ionic exchange reaction to synthesize ternary transition metal sulfide ball-in-ball hollow sphere (BHS) was applied as an efficient strategy to develop high performance electrode materials consisting of multilevel structures, which opened up new opportunities for varied applications, resulting in further improvement of the electrochemical performance [22,23]. Being one of the ternary transition metal sulfide, Zn-Co based mixed sulfide demonstrated excellent electrochemical properties and rendered it accessible for promising application in the field of electrochemistry, including supercapacitors [24,25], water splitting [26,27], and rechargeable battery [28,29]. These features made Zn-Co based mixed sulfide as a potentially ideal material for non-enzymatic glucose sensing.…”