Abstract:Aqueous polysulfide/iodide redox flow batteries are attractive for scalable energy storage due to their high energy density and low cost. However, their energy efficiency and power density are usually limited by poor electrochemical kinetics of the redox reactions of polysulfide/iodide ions on graphite electrodes, which has become the main obstacle for their practical applications. Here, CoS
2
/CoS heterojunction nanoparticles with uneven charge distribution, which are synthesized in sit… Show more
“…S6). The chemical shift of Co L 23 edge to higher energy was observed depending on higher S/Co ratio of cobalt sulfide 42 .Figure 2Microstructural and chemical characterization of MOF-driven porous CoS 2 nanoparticles. ( a ) TEM image after sulfurization of Co-PBAs.…”
Both high activity and mass production potential are important for bifunctional electrocatalysts for overall water splitting. Catalytic activity enhancement was demonstrated through the formation of CoS2 nanoparticles with mono-phase and extremely porous structures. To fabricate porous structures at the nanometer scale, Co-based metal-organic frameworks (MOFs), namely a cobalt Prussian blue analogue (Co-PBA, Co3[Co(CN)6]2), was used as a porous template for the CoS2. Then, controlled sulfurization annealing converted the Co-PBA to mono-phase CoS2 nanoparticles with ~ 4 nm pores, resulting in a large surface area of 915.6 m2 g−1. The electrocatalysts had high activity for overall water splitting, and the overpotentials of the oxygen evolution reaction and hydrogen evolution reaction under the operating conditions were 298 mV and −196 mV, respectively, at 10 mA cm−2.
“…S6). The chemical shift of Co L 23 edge to higher energy was observed depending on higher S/Co ratio of cobalt sulfide 42 .Figure 2Microstructural and chemical characterization of MOF-driven porous CoS 2 nanoparticles. ( a ) TEM image after sulfurization of Co-PBAs.…”
Both high activity and mass production potential are important for bifunctional electrocatalysts for overall water splitting. Catalytic activity enhancement was demonstrated through the formation of CoS2 nanoparticles with mono-phase and extremely porous structures. To fabricate porous structures at the nanometer scale, Co-based metal-organic frameworks (MOFs), namely a cobalt Prussian blue analogue (Co-PBA, Co3[Co(CN)6]2), was used as a porous template for the CoS2. Then, controlled sulfurization annealing converted the Co-PBA to mono-phase CoS2 nanoparticles with ~ 4 nm pores, resulting in a large surface area of 915.6 m2 g−1. The electrocatalysts had high activity for overall water splitting, and the overpotentials of the oxygen evolution reaction and hydrogen evolution reaction under the operating conditions were 298 mV and −196 mV, respectively, at 10 mA cm−2.
“…The formation of such a complex metal‐B structure has excellent oxidation resistance, which would significantly benefit the electrochemical properties. The peaks at 163.28 and 162.08 eV for S 2p are related to the metal‐S bonds (Figure e) . The peaks at 168.7 and 168.6 eV for S 2p are the intimations of SO bonds, suggesting the efficient filling of S in the vacancies …”
The development of efficient electrode materials is a cutting‐edge approach for high‐performance energy storage devices. Herein, an effective chemical redox approach is reported for tuning the crystalline and electronic structures of bimetallic cobalt/nickel–organic frameworks (Co‐Ni MOFs) to boost faradaic redox reaction for high energy density. The as‐obtained cobalt/nickel boride/sulfide exhibits a high specific capacitance (1281 F g−1 at 1 A g−1), remarkable rate performance (802.9 F g−1 at 20 A g−1), and outstanding cycling stability (92.1% retention after 10 000 cycles). An energy storage device fabricated with a cobalt/nickel boride/sulfide electrode exhibits a high energy density of 50.0 Wh kg−1 at a power density of 857.7 W kg−1, and capacity retention of 87.7% (up to 5000 cycles at 12 A g−1). Such an effective redox approach realizes the systematic electronic tuning that activates the fast faradaic reactions of the metal species in cobalt/nickel boride/sulfide which may shed substantial light on inspiring MOFs and their derivatives for energy storage devices.
“…11,12 Heterostructures are also capable of serving as highly active sites due to the synergistic effects arising from the interaction of different components. 13 Nevertheless, traditional technologies employ tedious procedures at high thermal budgets to produce these structures but with unsatisfactory controllability. 14 In addition to these atomic-scale and nanoscale structural features, the real performances also largely depend on the electrode architectures assembled by the electrode materials, while the easy and cost-effective fabrication of electrode architecture capable of rapid mass and/or charge transfer remains a formidable challenge.…”
Section: Progress and Potentialmentioning
confidence: 99%
“…[51][52][53] Recent advances have revealed that structural defects and heterostructures are of paramount importance in regulating the electronic configurations. 13,52 From the viewpoint of real application, the diffusion path of the active species within the electrode architectures also strongly affects the overall electrochemical performance. 2 As an emerging and highly efficient materials processing technology, laser irradiation has been widely used to precisely modulate the aforementioned structures, and its remarkable progress is summarized here and its advantages highlighted by comparing it with traditional strategies.…”
Section: Laser-mediated Structural Regulation Of Energy Materialsmentioning
In addition to its traditional use, laser irradiation has found extended application in controlled manipulation of electrode materials for electrochemical energy storage and conversion, which are primarily enabled by the laser-driven rapid, selective, and programmable materials processing at low thermal budgets. In this Review, we summarize the recent progress of laser-mediated engineering of electrode materials, with special emphases on its capability of controlled introduction of structural defects, precise fabrication of heterostructures, and elaborate construction of integrated electrode architecturesall of which are highly desired for many electrochemical processes, yet difficult to be precisely synthesized via conventional technologies. After a brief introduction of the fundamental mechanism of laser processing, its practical use for structural regulation of electrode materials is discussed in detail. The application of these laserenabled materials for supercapacitors, rechargeable batteries, and some fundamental electrocatalytic reactions enabling energy conversion is then summarized. Finally, we highlight the challenges faced at the current stage, aiming to shed some light on the future development of this prosperous field.
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