Multifunctional Electrode Research Articles

Three-dimensional nanoflower–like hierarchical array of multifunctional copper cobaltate electrode as efficient electrocatalyst for oxygen evolution reaction and energy storage application

The study deals with the hydrothermal growth of a CuCo2O4 hierarchical 3D nanoflower–like array on carbon cloth (CuCo2O4@CC), which is a useful multifunctional electrode. The electrocatalytic oxygen evolution reaction (OER) study of the CuCo2O4@CC electrode shows high durability and good activity in 1 M KOH. As an energy storage electrode, it shows a high specific capacitance of 1438 Fg−1 at 10 mA cm−2 in a 3 M KOH electrolyte. The electrochemical stability of the CuCo2O4@CC electrode was tested for 5000 cycles at 10 mA cm−2, and it showed 98.6% stability. This CuCo2O4@CC electrode produces a capacitance of 10 mA cm−2 at an overpotential of 288 mV for the OER, with a Tafel slope of 64.2 mV dev-1. The electrochemical stability measured at an overpotential of 292 mV for 12 h at 10 mA cm−2 shows good electronic stability in an alkaline medium. The enhanced electrochemical performance of the CuCo2O4@CC electrode may be due to the Cu and Co counterparts in addition to the high surface area. The CuCo2O4@CC electrode is a simple, flexible, and cost-effectivive electrode in both electrocatalytic OER and energy storage applications.

In-situ electro-generation and activation of hydrogen peroxide using a CuFeNLDH-CNTs modified graphite cathode for degradation of cefazolin

The modified multifunctional electrodes for electro-Fenton (EF) process are suggested to be promising cathodes for in situ electro-generation and activation of H2O2 to produce hydroxyl radicals (•OH). However, heterogeneous EF process still faces the challenges of limited catalytic activity and releasing of massive amounts of transition metals to the solution after removal of organic pollutants. The main aim of the present investigation was to prepare a cathode containing carbon nanotubes (CNTs) and CuFe nano-layered double hydroxide (NLDH) for degradation and mineralization of cefazolin antibiotic through electro-Fenton process. Structural and electrochemical analyses demonstrated that CuFeNLDH-CNTs nanocomposite was successfully incorporated on the surface of graphite cathode. Due to the increased formation of •OH in the reactor, the incorporation of CNTs into NLDH matrix with a catalyst loading of 0.1 g substantially improved the degradation efficiency of cefazolin (89.9%) in comparison with CNTs-coated (28.7%) and bare graphite cathode (22.8%) within 100 min. In the presence of 15 mM of ethanol, the degradation efficiency of cefazolin was remarkably decreased to 43.7% by the process, indicating the major role of •OH in the destruction of target molecules. Acidic conditions favored the degradation efficiency of cefazolin by the modified EF process. Mineralization efficiency of the bio-refractory compound was obtained to be 70.1% in terms of chemical oxygen demand (COD) analysis after 300 min. The gas chromatography-mass spectroscopy (GC-MS) analysis was also implemented to identify the intermediate byproducts generated during the degradation of cefazolin in the CuFeNLDH-CNTs/EF reactor.

Massive Growth of Graphene Quartz Fiber as a Multifunctional Electrode.

Quartz fiber, a widely used reinforcer with high tensile strength and excellent heat resistance, can have more attractive electrical applications such as electromagnetic interference shielding, static dissipation, and strain sensing if it becomes conductive. Many attempts have been made to increase the electrical conductivity of quartz fiber by surface coating of conductive polymers or plating of metal films, but suffers from sacrificing flexibility and causing heavy metal pollution. Here we designed and massively produced a hybrid structure of graphene quartz fiber (GQF) by a forced-flow chemical vapor deposition (CVD) method, which combines the excellent conductivity of graphene and the extraordinary properties of quartz fiber. The as-fabricated flexible GQF exhibited high sensitivity, fast response (<0.5 s) and good durability (∼5000 cycles) to organic solvent vapor, suitable as a real-time biomimetic gas sensor. Furthermore, the massively produced GQFs can be knitted into meter-scale fabrics with tunable conductivity (sheet resistances of 0.2-10 kΩ/sq) and superior electrothermal conversion efficiency (up to 980 °C within a few seconds at 24 V), thus propelling its promising application in industrial electric heaters. We expect this hybrid GQF material will greatly expand the applications of traditional quartz fiber into an infusive multifunctional regime.

Electrodeposited NiSe on a forest of carbon nanotubes as a free-standing electrode for hybrid supercapacitors and overall water splitting

NiSe nanoparticles are electrodeposited over a forest of carbon nanotubes (CNTs) to form an intertwined and porous network. The assynthesized composite (denoted as CNT@NiSe/SS) is used as a free-standing and multifunctional electrode for bothsupercapacitorsand overallwater splitting applications. For a supercapacitor application, CNT@NiSe/SS exhibits higher specific capacity and improved rate capability compared with individual NiSe and CNTs. A hybrid supercapacitor device consisting of battery-like CNT@NiSe/SS and EDLC-like graphene delivers a maximum energy density of 32.1 Wh kg−1 at a power density of 823 W kg−1 and has excellent stability after a floating test of 50 h. On the other hand, CNT@NiSe/SS also serves as a bifunctional electrocatalyst with high activity for overall water splitting. The CNT@NiSe/SS electrode displays excellent hydrogen and oxygen evolution reaction performance with the lowest overpotential of 174 mV at 10 mA cm−2 and 267 mV at 50 mA cm−2, respectively. The symmetrical two-electrode system requires an operating potential of 1.71 V to achieve a current density of 10 mA cm−2. Furthermore, this electrolyzer shows a negligible increment in potential after 24 hof continuouswater splitting. The outstanding performances of CNT@NiSe/SS can be attributed to the synergistic effect of NiSe and CNTs.

Engineering RuO2 on CuCo2O4/CuO nanoneedles as multifunctional electrodes for the hybrid supercapacitors and water oxidation catalysis

Abstract Currently, designing and constructing multifunctional electrodes is highly desirable for energy conversion and storage devices. Spinel cobaltites have attracted considerable attention owing to the relative high conductivity and rich redox chemistry, but the limited electroactive sites and poor surface chemical reactivity are the highly concerned issues. Taking Co–Cu oxides as the model material, here we demonstrate that a surface restructuring strategy by constructing core-shell arrays can achieve simultaneous modulation of electroactive sites and surface chemical reactivity. Strating from the hydrothermal and annealing process, CuCo2O4/CuO nanoneedles are synthesized directly on the conductive Ni foam, and followed by electrodeposited RuO2 nanoparticles (denoted as CuCo2O4/CuO@RuO2). Core-shell CuCo2O4/CuO@RuO2 arrays show a high areal capacity up to 862.5 mAh cm−2 and a high capacity retention of about 90.1% after 8000 cycles. Moreover, the hybrid supercapacitor by CuCo2O4/CuO@RuO2 and activated carbon can achieve 0.84 mWh cm−2 energy density at 8 mW cm−2 power density, as well as good long-term stability. In addtion, working as water oxidation catalysis, CuCo2O4/CuO@RuO2 shows the low overpotential of 279 mV at 10 mA cm−2, as well as a low Tafel slope and stable long-term performance. This work provides a novel strategy to engineer surface nanostructure for energy conversion and storage devices.

Metal ion-induced capacitance modulation in near-isostructural complexes-derived electrochromic coordination polymers

Coordination polymers and metal–organic frameworks have attracted immense attention across different fields of science as materials with numerous functional applications. Herein, we report the use of coordination polymers obtained from near-isostructural metal (Mn2+, Fe2+, and Co2+) bipyridine complexes as electrode materials in a symmetric supercapacitor test cell. The variation in the central metal ion (Mn2+ vs. Fe2+ vs. Co2+) in these nearly identical coordination complexes was found to dictate the capacitive performance of the coordination polymers obtained via Pd(II) cross-linking. The central metal ion not only influences the porosity, Brunauer–Emmett–Teller (BET) surface area (6.5 (Mn), 10.4 (Fe), and 29.7 (Co) m2/g), and the areal capacitance, but also the performance parameters such as the cycling stability and charge–discharge kinetics as well as the charge transfer mechanism. A 3:4:5 ratio for the areal capacitance values (9.1 (Mn), 12.2 (Fe), and 15.4 (Co) mF cm−2 at a scan rate of 5 mV/s) corroborates the modulative effect of the metal center. The cycling stabilities of these coordination polymers also followed the same order. At higher current densities (>0.50 mA cm−2), the supercapacitors fabricated from the Mn-coordination polymer were found to charge and discharge at faster rates, whereas those fabricated from Fe- or Co-coordination polymers continued to discharge at similar rates, indicating similar pore volumes for the latter as confirmed by BET surface area measurements. Although the materials used in this study resulted in modest capacitive performance, the possibilities to enhance their surface area and crystallinity is envisaged to result in the development of new, multifunctional non-carbon electrode materials with efficient electrochemical storage characteristics and tunable electro-optical properties.

Interweaving between MnO2 nanowires/ nanorods and carbon nanotubes as robust multifunctional electrode for both liquid and flexible electrochemical energy devices

In this paper, as a proof-of-concept study, a newly designed multifunctional composite electrode materials consisting of an interweaving structure of MnO2 nanowires (NWs)/nanorods (NRs) and carbon nanotubes (CNTs) (MnO2-NWRs/CNTs) are directly synthesized by a facile and scalable strategy, which show high catalytic activity for both oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) processes and large specific capacitance for supercapacitors (SCs). Such a MnO2-NWRs/CNTs350 material is induced by the strong coupling and synergistic effect between MnO2-NWRs and CNTs, as well as the coexistence of NRs/NWs and the existence of favorable crystal planes, which enable the multifunctional high-performance in zinc-air batteries (ZABs), magnesium-air batteries (MABs), SCs and also their flexible devices. The MnO2-NWRs/CNTs350 catalyst exhibits high electrochemical activity (ΔE: 0.98 V), decent capacitance (1183 F g−1) and excellent battery performance (specifically, 640 mW cm−2 for MABs). In MnO2-NWRs/CNTs350, the (110) and (101) crystal planes of MnO2-NWRs are advantageous for both ORR and OER processes. Additionally, the structural changes of MnO2-NWRs/CNTs350 (the coexistent NRs and NWs) improve the capacitance of the material. Even more encouraging, the interweaving structure endows the flexible rechargeable MABs, ZABs, and SCs with excellent electrochemical performance in terms of both activity and stability.

Rational rope-like CuCo2O4 nanosheets directly on Ni foam as multifunctional electrodes for supercapacitor and oxygen evolution reaction

Transition metal oxides have shown promising candidates for energy storage and conversion devices, but the limited electroactive sites may greatly limit the further improvement. Herein, we successfully achieve rope-like CuCo2O4 nanosheets directly on Ni foam, which acts as multifunctional electrodes for supercapacitor and oxygen evolution reaction (OER). The rope-like nanosheets with the ultrathin thickness and large surface areas can effectively increase the number of active sites, resulting in enhanced electrochemical performances. In addition, directly growing nanostructures on conductive Ni foam can endows the electrode materials with higher conductivity and richer active sites. Consequently, obtained rope-like CuCo2O4 nanosheets show the superior electrochemical performances toward supercapacitor and OER. In detail, obtained rope-like CuCo2O4 nanosheets display a high capacity of 5.84 F cm−2 (0.65 mAh cm−2) at 5 mA cm−2, as good as good stability. The asymmetric supercapacitor made of CuCo2O4 (positive electrode) and activated carbon (negative electrode) also show a high energy density of 0.55 mWh cm−2 at 8 mW cm−2 power density. In addition, obtained rope-like CuCo2O4 nanosheets only require a low overpotential of 220 mV at 10 mA cm−2 for OER, and also maintain the outstanding long-term durability. These remarkable performances of rope-like CuCo2O4 hold great promise for energy storage and conversion devices.

Engineering of electrodeposited binder-free organic-nickel hydroxide based nanohybrids for energy storage and electrocatalytic alkaline water splitting

A binder-free electrodeposited organic–inorganic multifunctional nanohybrid electrode exhibits high specific capacitance with electrocatalytic water splitting performance.

Binary graphene-based cathode structure for high-performance lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are highly appealing for the next-generation of energy storage because of their high energy density and low-cost features. However, the practical implementation of Li-S batteries has been hindered by fast performance degradation of the sulfur cathode, especially at a high cathode loading. Here, we propose a strategic design of binary graphene foam (BGF) as the cathode scaffold, with the incorporation of nitrogen-doped graphene and highly porous graphene. The nitrogen-doped graphene provides chemical adsorption sites for migrating polysulfides, and the highly porous graphene could increase the cathode conductivity and accelerate lithium ion transport. The freestanding foam-like cathode structure further offers a robust, interconnected, conductive framework to promote the redox reaction even at a high cathode loading. Therefore, the Li-S battery with the S/BGF electrode exhibits a high specific areal capacity over 10 mAh cm–2 and good cycling stability over 300 cycles. This approach offers insights into multifunctional electrode structure design, with targeted functions for high-performance Li-S batteries.

Three dimensional Ni3S2 nanorod arrays as multifunctional electrodes for electrochemical energy storage and conversion applications.

The increasing demand for energy and environmental protection has stimulated intensive interest in fundamental research and practical applications. Nickel dichalcogenides (Ni3S2, NiS, Ni3Se2, NiSe, etc.) are promising materials for high-performance electrochemical energy storage and conversion applications. Herein, 3D Ni3S2 nanorod arrays are fabricated on Ni foam by a facile solvothermal route. The optimized Ni3S2/Ni foam electrode displays an areal capacity of 1602 µA h cm−2 at 5 mA cm−2, excellent rate capability and cycling stability. Besides, 3D Ni3S2 nanorod arrays as electrode materials exhibit outstanding performances for the overall water splitting reaction. In particular, the 3D Ni3S2 nanorod array electrode is shown to be a high-performance water electrolyzer with a cell voltage of 1.63 V at a current density of 10 mA cm−2 for overall water splitting. Therefore, the results demonstrate a promising multifunctional 3D electrode material for electrochemical energy storage and conversion applications.

Constructing Multichannel Carbon Fibers as Freestanding Anodes for Potassium‐Ion Battery with High Capacity and Long Cycle Life

AbstractPotassium‐ion battery (PIB) is a potential low‐cost energy storage technology owing to the abundant source and wide distribution of potassium element. However, the PIB usually suffers from poor cycling and rate performance induced by volume expansion and sluggish potassiation kinetics. Herein, multichannel carbon fibers (MCCFs) are rationally constructed as freestanding PIB anodes by electrospinning suitable ratio of poly(methyl methacrylate)/polyacrylonitrile with subsequent calcination treatment. The MCCF electrode shows a high reversible capacity/charge capacity of 420.1/304.2 mAh g−1 at current density of 50 mA g−1 and delivers a capacity of 110.9 mAh g−1 over 2000 cycles at a higher current density of 2000 mA g−1. The excellent electrochemical performance is attributed to the unique multichannels in amorphous MCCFs for buffering volume change and facilitating electrolyte infiltration, as well as high conductivity of N‐, O‐doping in MCCFs. This strategy of fabricating multifunctional electrode materials provides an effective approach to develop high‐performance materials for cost‐effective alkali‐ion batteries.

PEDOT: Fundamentals and Its Nanocomposites for Energy Storage

PEDOT, or poly(3,4-ethylenedioxythiophene), is among the most successful conducting polymer products because of its stable conductivity, colloidal processability, and rich assembly behavior. Since the very first patents on PEDOT filed in 1988, the material has been widely explored for decades in many applications. In this review, a comprehensive summary on the synthesis, processing and post-treatment of PEDOT will be presented for the sake of the discussion on PEDOT and its nanocomposites for energy storage. Knowing what PEDOT lends itself to the electrode materials is of importance to the rational design of energy storage devices that maximize the real-world performance. Based on these discussions, a roadmap for the development of PEDOT as promising multifunctional electrode component is presented.

Hierarchically Porous C/Fe3C Membranes with Fast Ion-Transporting Channels and Polysulfide-Trapping Networks for High-Areal-Capacity Li-S Batteries.

We report here highly scalable yet stackable C/Fe3C membranes with fast ion-transport micro-/nanochannels and polysulfide-trapping networks via a facile phase-inversion process for high-areal-capacity Li-S batteries. The membrane cathodes with aligned channels and hierarchically porous networks significantly promote Li+ and electron transportation and meanwhile trap soluble polysulfide intermediates (LiPSs) effectively via strong chemical adsorption of the doped Fe3C nanoparticles in the membrane toward LiPSs. We further demonstrated that five-layer membrane electrodes with high S loading of 7.1 mg cm-2 were readily prepared via layer-by-layer stacking of the C/Fe3C membrane, which can deliver a high capacity of 726 mA h g-1 after 100 cycles, corresponding to an ultra-high-areal-capacity of 5.15 mA h cm-2 at a low electrolyte/sulfur (E/S) ratio of 6.4 μL mg-1. The scalable multifunctional membrane electrodes with excellent electrochemical performance under high-sulfur-loading and lean electrolyte conditions reveal its promising applications in practical Li-S batteries.

Multifunctional FeS2 in binder-independent configuration as high-performance supercapacitor electrode and non-enzymatic H2O2 detector

Multifunctional FeS2 electrode that holds great promise for energy storage and biological application is developed in the present study in a binder-less configuration. X-ray diffractometry, Raman and X-ray photoelectron spectroscopy, high-resolution transmission and scanning electron microscopy reveals that such electrode design is characterized by a dense and well-ordered array made of highly crystalline FeS2 nanotubes directly built on a variety of conductive substrates. The characteristic solid contact and the open framework in such binder-free scheme synergistically well strengthen the functionality of FeS2 as on the one hand a highly appealing supercapacitor electrode to deliver an outstanding specific capacitance amounted to 320 F/g along with an excellent energy density of 78.7 Wh/kg and a power delivery of 8.81 kW/kg, respectively, upon coupled with MnO2 to build an asymmetric supercapacitor. Moreover, the FeS2 electrode on the other hand as an enzyme-free biosensor is also highly competitive in view of the high selectivity and the superior sensitivity of 612 μA/mM cm2 to electrochemically detect ultradiluted H2O2 at a concentration of only 0.25 μM.

Electrocatheter-mediated High-voltage Pulsed Radiofrequency of the Dorsal Root Ganglion in the Treatment of Chronic Lumbosacral Neuropathic Pain: A Randomized Controlled Study.

Objectives:Despite the interest in scientific community, there is still poor evidence about pulsed radiofrequency (PRF) efficacy in the treatment of neuropathic pain. In order to determine whether high-voltage PRF and epidural adhesiolysis (PRF-EA) showed better results than epidural adhesiolysis alone (EA), a randomized, double-blind, comparative-effectiveness study was conducted in patients with chronic lumbosacral radiating pain and neuropathic features.Materials and Methods:A total of 41 patients were randomly allocated to 2 groups. Twenty-one patients were randomized to receive 2 cycles of 240 seconds high-voltage PRF followed by the injection of local anesthetics, hyaluronidase, and betamethasone, whereas 20 patients underwent sham stimulation followed by adhesiolysis. The treatment was delivered at the affected lumbosacral roots and patients, treating physicians and assessors were blinded to intervention.Results:A significant reduction of radiating pain was observed in mean Numeric Rating Scale score at follow-up. A change of −3.43 versus −1.75 (P=0.031) after 1 month and −3.34 versus −0.80 (P=0.005) after 6 months was reported in patients undergoing PRF-EA in comparison with EA, respectively. After 1 month, 57% of patients in the PRF-EA group experienced a pain reduction of ≥50% versus only 25% of patients allocated to EA (P=0.037). Improvement decreased to 48% in the PRF-EA group whereas only 10% of EA reported significant pain relief after 6 months (P=0.008).Discussion:High-voltage PRF of dorsal root ganglion delivered through multifunctional electrode provided significant pain relief and may be considered a valuable treatment in chronic lumbosacral radicular pain with neuropathic features.

High Electrochemical Performance and Enhanced Electrocatalytic Behavior of a Hydrothermally Synthesized Highly Crystalline Heterostructure CeO2@NiO Nanocomposite.

A CeO2-based heterostructure nanocomposite has been attractive as an electrode material for energy storage and as an electrochemical sensor. In the present work, a CeO2@NiO nanocomposite was prepared by a simple hydrothermal method. The structural and morphological information on the heterostructure CeO2@NiO nanocomposite were obtained by using different characterization methods like X-ray diffraction, UV-visible, Fourier transform infrared, electron paramagnetic resonance, Raman, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray elemental color mapping, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Compared with pristine CeO2, the heterostructure CeO2@NiO nanocomposite exhibits a higher electrochemical performance with a specific capacitance of 317 F g-1 at a current density of 1 A g-1 in a 1 M KOH electrolyte. This device demonstrates a high energy density and a power density of 11 Wh kg-1 and 750 W kg-1, respectively. Besides, it was found that CeO2@NiO/glassy carbon electrode (GCE) shows appreciable electrocatalytic activity toward NO2- oxidation. The CeO2@NiO-modified electrode displays a linear response for NO2- oxidation between 0.001 × 10-6 and 4 × 10-3 M. Apart from high sensitivity (2260 μA mM-1 cm-2), the CeO2@NiO-modified electrode also exhibits good selectivity and long-term stability for nitrite (NO2-) detection in a water real sample, and the obtained results showed excellent recovery. The encouraging electrochemical performance of the CeO2@NiO nanocomposite provides a promising approach for the development of multifunctional electrode materials for future energy storage devices and sensors.

Kirigami-inspired strain-insensitive sensors based on atomically-thin materials

Abstract This work reports kirigami-inspired architectures of graphene for strain-insensitive, surface-conformal stretchable multifunctional electrodes and sensors. The kirigami-inspired graphene electrode exhibits strain-insensitive electrical properties up to 240% applied tensile strain and mixed strain states, including a combination of stretching, twisting, and/or shearing. Moreover, a multitude of kirigami designs of graphene are explored computationally to predict deformation morphologies under different strain conditions and to achieve controllable stretchability. Notably, strain-insensitive graphene field-effect transistor and photodetection under 130% stretching and 360° torsion are achieved by strategically redistributing stress concentrations away from the active sensing elements via strain-responsive out-of-plane buckling at the vicinity of the kirigami notches. The combination of ultra-thin form factor, conformity on skin, and breathable notches suggests the applicability of kirigami-inspired platform based on atomically-thin materials in a broader set of wearable technology.

Controllable Tuning of Cobalt Nickel-Layered Double Hydroxide Arrays as Multifunctional Electrodes for Flexible Supercapattery Device and Oxygen Evolution Reaction.

The rational design and fabrication of promising electrodes with prominent energy storage property and conversion performance is crucial for supercapacitors and electrocatalysis. Herein, potato chip-like cobalt nickel-layered double hydroxide@polypyrrole-cotton pad (CoNi-LDH@PCPs) composite was synthesized by in situ polymerization, which was coupled with facile solution reaction and ion-exchange etching process. An interesting potato chip-like structure can effectively expedite the kinetics of the electrode reactions, while the three-dimensional PCPs texture affords efficient pathways for charge transport, and the voids between adjacent fibers are thoroughly accessible for electrolytes and bubble evolution. When evaluated as a positive electrode for wearable supercapattery, the hierarchical CoNi-LDH@PCPs electrode displayed high specific capacity and excellent flexibility. As an oxygen evolution reaction catalyst, this PCP-based electrode also reveals the lowest overpotential of 350 mV at 10 mA cm-2 and a Tafel slope of ∼58 mV dec-1. In addition, density functional theory calculations suggest that the synthesis strategy for controllable tuning of hollow CoNi-LDH arrays reported here represents a critical step toward high-performance electrodes for energy storage and electrochemical catalysis.

An electrodeposited amorphous cobalt sulphide nanobowl array with secondary nanosheets as a multifunctional counter electrode for enhancing the efficiency in a dye-sensitized solar cell

Light trapping by the ordered nanostructure of a photoanode has been considered to be an effective way to improve the photovoltaic performance of a dye-sensitized solar cell (DSSC), but it is rarely reported for the counter electrode. In the present work, a two-dimensional cobalt sulphide (Co-S) nanobowl array with a hierarchical structure has been designed for the counter electrode with a light scattering effect and fabricated by a potential reversal electrodeposition technique. The Co-S nanobowl array is amorphous with secondary nanosheets. Due to lattice distortions and more edge-sites with dangling bonds, the amorphous phase increases the catalytic activity for electrolyte regeneration. Additionally, the Co-S nanobowl array with ordered hierarchical pores is beneficial for the diffusion of the I−/I3− redox couples. The DSSC assembled with Co-S nanobowl array exhibits excellent photovoltaic performance with a champion power conversion efficiency (PCE) as high as 7.78%, which is larger than those of DSSC assembled with Pt (6.51%) and Co-S (7.14%) counter electrodes. Hence, the Co-S nanobowl array is a multifunctional counter electrode for superior electrocatalytic performance and light scattering effect.