Dong-Wook Han

Prioritization and selection of intellectual capital measurement indicators using analytic hierarchy process for the mobile telecommunications industry

Intellectual capital (IC) has prevailed as a measure of core competency and competitive advantage which explains the gap between the market value and book value of an organization at a time of decreasing usefulness of current financial reporting. In spite of the importance of IC management (ICM), few applicable ICM methodologies have been addressed. There has been no basis model for IC statements, nor bottom-line indicators of the value of IC. The selection of effective IC indicators is a major task of the companies that are preparing IC reports. This paper has proposed a decision model based on the analysis of the conceptual framework of the qualitative characteristics of financial information and an examination of information quality of the information system. The application of the analytic hierarchy process makes it possible to extract weights for setting the priority among criteria in the mobile telecommunications industry. During the last decade, this industry has experienced a dramatic growth in its intellectual value, and the value of IC seems to have had a major impact on the value of the mobile telecommunications companies. Based on specified criteria and weighting, this paper presents the results of a case study illustrating the results of selected indicators from candidate indicators in the mobile telecommunications company.

Structural enhancement of Na3V2(PO4)3/C composite cathode materials by pillar ion doping for high power and long cycle life sodium-ion batteries

Structurally stabilized Na3V2(PO4)3/C composite cathode materials with excellent electrochemical performance can be obtained by incorporating functional pillar ions into the structure. As pillar ions, K-ions have a larger ionic radius compared to Na-ions, and play an important role in enlarging the Na-ion diffusion pathway and in increasing the lattice volume by elongating the c-axis, thereby improving the rate performance. Furthermore, since the incorporated K-ions rarely participate in the electrochemical extraction/insertion reactions, they can stabilize the Na3V2(PO4)3 structure by suppressing significant lattice volume changes or structural distortion, even in a wide range of voltage windows accompanying multiple transitions of V ions and phase distortions. We investigated how the K-ion doping level affected the crystal structure and electrochemical properties of Na3V2(PO4)3 cathode materials for Na-ion batteries.

Na3V2(PO4)3 particles partly embedded in carbon nanofibers with superb kinetics for ultra-high power sodium ion batteries

We here describe the extraordinary performance of NASICON Na3V2(PO4)3-carbon nanofiber (NVP–CNF) composites with ultra-high power and excellent cycling performance. NVP–CNFs are composed of CNFs at the center part and partly embedded NVP nanoparticles in the shell. We first report this unique morphology of NVP–CNFs for the electrode material of secondary batteries as well as for general energy conversion materials. Our NVP–CNFs show not only a high discharge capacity of ∼88.9 mA h g−1 even at a high current density of 50 C but also ∼93% cyclic retention property after 300 cycles at 1 C. The superb kinetics and excellent cycling performance of the NVP–CNFs are attributed to the facile migration of Na ions through the partly exposed regions of NVP nanoparticles that are directly in contact with an electrolyte as well as the fast electron transfer along the conducting CNF pathways.

Fabrication of Graphene Embedded LiFePO4 Using a Catalyst Assisted Self Assembly Method as a Cathode Material for High Power Lithium-Ion Batteries

We have designed a unique microstructure of graphene embedded LiFePO4 by a catalyst assisted self assembly method as a cathode material for high power lithium-ion batteries. The stable amide bonds between LiFePO4 and graphene were formed by the catalyst assisted self assembly. High conductive graphene provides a fast electron transfer path, and many pores inside the structure facilitate the lithium-ion diffusion. The graphene embedded LiFePO4 fabricated by the novel method shows enhanced cycling performance and rate-capability compared with that of carbon coated LiFePO4 as a cathode material for high power lithium-ion batteries.

Synergistic effects of various morphologies and Al doping of spinel LiMn2O4 nanostructures on the electrochemical performance of lithium-rechargeable batteries

Nanostructured electrodes have recently received great attention as components in lithium rechargeable batteries, especially because of the high power produced by the fast kinetic properties of these unique structures. Here, we report the successful synthesis of various nanostructured morphologies of spinel lithium manganese oxide electrodes (nanorod, nanothorn sphere, and sphere) from a similarly shaped manganese dioxide precursor that was controlled with different aluminium contents by the hydrothermal method. Among these structures, nanothorn sphere structured LiAl0.02Mn1.98O4 produces the highest discharge capacity of 129.8 mA h g−1, excellent rate capability (94.6 mA h g−1 at 20 C, 72% of 0.2 C-rate discharge capacity) and stable cyclic retention for 50 cycles. The excellent kinetic properties of the nanothorn sphere structure are not only due to the nanothorn sphere electrode having high surface area but also because the critical amount of Al in the nanothorn sphere electrode was located at the Mn site (16d) instead of the Li site (8a).

Structurally stabilized olivine lithium phosphate cathodes with enhanced electrochemical properties through Fe doping

Controlling the crystallographic structure in olivine lithium phosphates is crucial for obtaining superior electronic (J. Electrochem. Soc., 2002, 149, A1184-A1189) and ionic conductivities (Electrochem. Solid-State Lett., 2006, 9, A352-A355; Electrochem. Solid-State Lett., 2006, 9, A439-A442; Nat. Mater., 2002, 1, 123-128), and stability, for use as cathodes in lithium batteries. Here, we report a completely new approach to enhance Li+ extraction and transport in LiCoPO4 through Fe doping. We show that preferential Fe occupation of the 4c sites suppresses 4a–4c antisite mixing of Li and Co, thereby stabilizing the olivine structure by compensating for the Co-encapsulating oxygen octahedron shrinkage due to Co2+ oxidation during Li+ extraction. The structural stabilization gives rise to ∼10% higher charge capacity at a two-fold lower resistance than the undoped counterparts besides accelerating the intercalation/extraction kinetics. Our findings provide key atomistic-level insights that pave the way for the rational design and realization of new types of metal-doped cathode materials for lithium batteries and related applications.

Effects of Substrate Morphology and Postelectrodeposition on Structure of Cu Foam and Their Application for Li-Ion Batteries

bubbles are split into small bubbles by the nodules. In addition, the adhesive properties of the Cu foamdeposited on the nodular Cu foil are improved by the mechanical interlocking effects of the nodules. As a result of the postelec-trodeposition treatment, the mechanical strength of the Cu foam is significantly enhanced primarily due to the covering of thepost-Cu electrodeposit on the dendrite crystallites of the Cu foam. The Li capacity and cycle performances of a Sn anode areclearly improved when Sn is electrodeposited on the covered Cu foam on the nodular Cu foil compared with that on the uncoveredCu foam: 451 mAh g