Young Soo Yun

Novel carbon-based microporous nanoplates containing numerous heteroatoms (H-CMNs) are fabricated from regenerated silk fibroin by the carbonization and activation of KOH. The H-CMNs exhibit superior electrochemical performance, displaying a specific capacitance of 264 F/g in aqueous electrolytes, a specific energy of 133 Wh/kg, a specific power of 217 kW/kg, and a stable cycle life over 10000 cycles.

The nanostructure design of porous carbon-based electrode materials is key to improving the electrochemical performance of supercapacitors. In this study, hierarchically porous carbon nanosheets (HP-CNSs) were fabricated using waste coffee grounds by in situ carbonization and activation processes using KOH. Despite the simple synthesis process, the HP-CNSs had a high aspect ratio nanostructure (∼20 nm thickness to several micrometers in lateral size), a high specific surface area of 1945.7 m(2)

The galvanostatic lithiation/sodiation voltage profiles of hard carbon anodes are simple, with a sloping drop followed by a plateau. However, a precise understanding of the corresponding redox sites and storage mechanisms is still elusive, which hinders further development in commercial applications. Here, a comprehensive comparison of the lithium- and sodium-ion storage behaviors of hard carbon is conducted, yielding the following key findings: 1) the sloping voltage section is presented by the

Pyroprotein-based carbon nanoplates are fabricated from self-assembled silk proteins as a versatile platform to examine sodium-ion storage characteristics in various carbon environments. It is found that, depending on the local carbon structure, sodium ions are stored via chemi-/physisorption, insertion, or nanoclustering of metallic sodium.

Abstract Because of its remarkably high theoretical capacity and favorable redox voltage (−2.71 V vs the standard hydrogen electrode), Na is a promising anode material for Na ion batteries. In this study, macroporous catalytic carbon nanotemplates (MC‐CNTs) based on nanoweb‐structured carbon nanofibers with various carbon microstructures are prepared from microbe‐derived cellulose via simple heating at 800 or 2400 °C. MC‐CNTs prepared at 800 °C have amorphous carbon structures with numerous topo

Advanced nanostructured hybrid materials can help us overcome the electrochemical performance limitations of current energy storage devices. In this study, three-dimensional porous carbon nanowebs (3D-CNWs) with numerous included orthorhombic Nb 2 O 5 (T-Nb 2 O 5 ) nanoparticles were fabricated using a microbe-derived nanostructure. The 3D-CNW/T-Nb 2 O 5 nanocomposites showed an exceptionally stable long-term cycling performance over 70 000 cycles, a high reversible capacity of ∼125 mA h g –1, a

Nitrogen- and micropore-containing carbon nanotubes (NMCNTs) were prepared by carbonization of nitrogen-enriched, polymer-coated carbon nanotubes (CNTs), and the electrochemical performances of the NMCNTs with different heteroatom contents were investigated. NMCNTs-700 containing 9.1 wt% nitrogen atoms had a capacitance of 190.8 F/g, which was much higher than that of pristine CNTs (48.4 F/g), despite the similar surface area of the two CNTs, and was also higher than that of activated CNTs (151.

Abstract Ultra‐thin hollow carbon nanospheres (UTH‐CNs) are fabricated for use as anodes of asymmetric sodium ion pseudocapacitors. The ∼3 nm thick amorphous carbon walls obtained from regenerated silk proteins as a template exhibit a well‐defined porous structure suitable for reversible sodium‐ion storage. The UTH‐CNs show remarkable electrochemical activity with sodium via a pseudocapacitive reaction, delivering a large reversible capacity as well as superior rate performance for more than 100

Intercalation-based anode materials for Na-ion batteries show relatively unfavorable electrochemical performances compared with those of Li-ion batteries because of the larger and heavier Na ion, as well as its higher electrode potential. In contrast, conversion-reaction-based anode materials have great potential for use in Na-ion batteries. In this study, copper sulfide nanodisks (CuS-NDs) were fabricated by a simple low-temperature reaction and applied as the anode materials for Na-ion batteri

Abstract Anode‐free sodium metal batteries (AF‐SMBs) can deliver high energy and enormous power, but their cycle lives are still insufficient for them to be practical as a power source in modern electronic devices and/or grid systems. In this study, a nanohybrid template based on high aspect‐ratio silver nanofibers and nitrogen‐rich carbon thin layers as a core–shell structure is designed to improve the Coulombic efficiency (CE) and cycling performance of AF‐SMBs. The catalytic nanohybrid templa