Jung-In Lee

Mesoporous CuO Particles Threaded with CNTs for High‐Performance Lithium‐Ion Battery Anodes

Mesoporous CuO particles threaded with carbon nanotubes are suggested as a novel class of nanocomposite material for a high-performance anode in the lithium-ion batteries. The nanocomposite electrode exhibits a highly reversible capacity (650 mA h g(-1) at 0.1 C rate) and an excellent C rate capability (580 mA h g(-1) at 5 C, and 500 mA h g(-1) at 10 C).

Highly stable Si-based multicomponent anodes for practical use in lithium-ion batteries

We demonstrate a simple process to synthesize silicon-based multicomponents via a high-temperature annealing of bulk silicon monoxide in the presence of sodium hydroxide. The carbon-coated Si-based anodes exhibit a highly stable cycling performance (capacity retention of 99.5% after 200 cycles) with a reversible charge capacity of 1280 mA h g−1.

Helical Silicon/Silicon Oxide Core–Shell Anodes Grown onto the Surface of Bulk Silicon

We demonstrate a simple route for preparing Si/SiO(x) urchin-like structures in which Si/SiO(x) core-shell nanocoils protruded out from the surface of bulk Si, via high-temperature annealing of Pt-decorated Si powders. The carbon-coated urchin-like anodes with micro- and nanostructured composite exhibit a significantly improved electrochemical performance with a high specific capacity of 1600 mAh/g and a superior cycling performance of 70 cycles at a rate of 0.2 C due to the nanocoil conformation and SiO(x) buffer layer. More importantly, the composite results in a significantly enhanced the volumetric capacity with ∼3780 mAh/cc, compared to bulk Si (∼2720 mAh/cc) after fully lithiation to 0 V.

Chemical‐Assisted Thermal Disproportionation of Porous Silicon Monoxide into Silicon‐Based Multicomponent Systems

Under the surface: Ag nanoparticles are deposited onto the surface of commercially available SiO particles, and subsequent chemical etching results in the formation of nanoporous SiO without changing the chemical and physical properties of the original SiO. Moreover, chemical-assisted thermal annealing produces a shape-preserving Si-based multicomponent system, which exhibits high-performance electrochemical properties.

High-performance silicon-based multicomponent battery anodes produced via synergistic coupling of multifunctional coating layers

Nanostructured Si-based materials are key building blocks for next-generation energy storage devices. To meet the requirements of practical energy storage devices, Si-based materials should exhibit high-power, low volume change, and high tap density. So far, there have been no reliable materials reported satisfying all of these requirements. Here, we report a novel Si-based multicomponent design, in which the Si core is covered with multifunctional shell layers. The synergistic coupling of Si with the multifunctional shell provides vital clues for satisfying all Si anode requirements for practical batteries. The Si-based multicomponent anode delivers a high capacity of ∼1000 mA h g−1, a highly stable cycling retention (∼65% after 1000 cycles at 1 C), an excellent rate capability (∼800 mA h g−1 at 10 C), and a remarkably suppressed volume expansion (12% after 100 cycles). Our synthetic process is simple, low-cost, and safe, facilitating new methods for developing electrode materials for practical energy storage.

High-performance Si anodes with a highly conductive and thermally stable titanium silicide coating layer

We report a simple route for synthesizing titanium silicide-coated Si anodes via the silicothermic reduction process of TiO2-coated Si. The titanium silicide enhances the electrical conductivity of Si nanoparticles and provides a highly stable solid electrolyte interface layer during the cycling, resulting in excellent electrochemical performances and significantly improved high thermal stability.

Multifunctional molecular design as an efficient polymeric binder for silicon anodes in lithium-ion batteries.

This work demonstrates the design, synthesis, characterization, and study of the electrochemical performance of a novel binder for silicon (Si) anodes in lithium-ion batteries (LIBs). Polymeric binders with three different functional groups, namely, carboxylic acid (COOH), carboxylate (COO(-)), and hydroxyl (OH), in a single polymer backbone have been synthesized and characterized via (1)H NMR and FTIR spectroscopies. A systematic study that involved varying the ratio of the functional groups indicated that a material with an acid-to-alcohol molar ratio of 60:40 showed promise as an efficient binder with an initial columbic efficiency of 89%. This exceptional performance is attributed to the strong adhesion of the binder to the silicon surface and to cross-linking between carboxyl and hydroxyl functional groups, which minimize the disintegration of the Si anode structure during the large volume expansion of the lithiated Si nanoparticle. Polymers with multiple functional groups can serve as practical alternative binders for the Si anodes of LIBs, resulting in higher capacities with less capacity fade.

Catalyst-free synthesis of Si-SiOx core-shell nanowire anodes for high-rate and high-capacity lithium-ion batteries.

Si-SiOx core-shell nanowires (NWs) ranging from 10 to 30 nm in diameter are prepared by a simple evaporation of silicon monoxide and control of substrate temperatures without any catalyst. The Si-SiOx NWs grown at 735 and 955 °C are strongly anchored to the Cu current collector by forming copper silicide at the interface between Si and Cu, and subsequently used as anodes in lithium-ion batteries, in which no binder or conducting materials are used. The Si-SiOx NWs anodes show excellent electrochemical performances in terms of capacity retention and rate capability. In particular, the Si-SiOx NW anode grown at 955 °C shows a reversible capacity of ∼1000 mAh g(-1) even at a high-rate of 50 C. This catalyst-free synthetic route of Si-SiOx NWs that are strongly anchored to the Cu current collector opens up an effective process for fabricating other high-capacity anodes in lithium-ion batteries (LIBs).

Large‐Scale Synthesis of Interconnected Si/SiOx Nanowire Anodes for Rechargeable Lithium‐Ion Batteries

Down to the wire: Three-dimensional interconnected Si-based nanowires are produced through the combination of thermal decomposition of SiO and a metal-catalyzed nanowire growth process. This low-cost and scalable approach provides a promising candidate for high-capacity anodes in lithium-ion batteries.

Patterning of electrodes for mechanically robust and bendable lithium-ion batteries

We demonstrate a simple route for fabricating trench-type copper patterns by combining a photo-lithography with a wet etching process. Nanostructured CuO was grown on the patterned Cu current collectors via a simple solution immersion process. And silicon nanoparticles were filled into the patterned Cu current collectors. The strongly immobilized CuO on the patterned Cu exhibited high electrochemical performance, including a high reversible capacity and a high rate capability.