Hanyang University

About: Hanyang University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Thin film & Population. The organization has 29387 authors who have published 58815 publications receiving 1190144 citations. The organization is also known as: Hanyang Taehakkyo.

Synthesis of Nanowire and Hollow LiFePO4 Cathodes for High-Performance Lithium Batteries

Abstract: The synthesis of nanowire and hollow LiFePO4 cathodes using the hard templates KIT-6 and SBA-15 is reported for high-performance lithium batteries. The two-dimensional hexagonal SBA-15 silica template with P6mm symmetry is used for the template that contains parallel cylindrical pores arranged with hexagonal symmetry, which serves to organize the wires into parallel bundles. On the other hand, three-dimensional cubic arrangement of pores in KIT-6 silica with Ia3d symmetry yields hollow morphology with mesopores. After impregnation of the template into a solution or after coating on the template with a solution consisting of LiFePO4 precursors, the silica template is removed and is subsequently fired at 700 °C. Electrochemical cycling of both the nanowire and hollow LiFePO4 cathodes demonstrates excellent rate capability even above 10C rate, showing >89% capacity retention of the initial capacity. Among them, the rate capability of the hollow cathode at 15C is higher than that of the nanowire cathode, show...

Understanding the behavior of Li–oxygen cells containing LiI

Abstract: Mankind has been in an unending search for efficient sources of energy. The coupling of lithium and oxygen in aprotic solvents would seem to be a most promising direction for electrochemistry. Indeed, if successful, this system could compete with technologies such as the internal combustion engine and provide an energy density that would accommodate the demands of electric vehicles. All this promise has not yet reached fruition because of a plethora of practical barriers and challenges. These include solvent and electrode stability, pronounced overvoltage for oxygen evolution reactions, limited cycle life and rate capability. One of the approaches suggested to facilitate the oxygen evolution reactions and improve rate capability is the use of redox mediators such as iodine for the fast oxidation of lithium peroxide. In this paper we have examined LiI as an electrolyte and additive in Li oxygen cells with ethereal electrolyte solutions. At high concentrations of LiI, the presence of the salt promotes a side reaction that forms LiOH as a major product. In turn, the presence of oxygen facilitates the reduction of I3− to 3I− in these systems. At very low concentrations of LiI, oxygen is reduced to Li2O2. The iodine formed in the anodic reaction serves as a redox mediator for Li2O2 oxidation.

Remaining Useful Life Prediction of Lithium-Ion Batteries Based on Spherical Cubature Particle Filter

Abstract: Lithium-ion batteries are critical components to provide power sources for commercial products. To ensure a high reliability of lithium-ion batteries, prognostic actions for lithium-ion batteries should be prepared. In this paper, a prognostic method is proposed to predict the remaining useful life (RUL) of lithium-ion batteries. A state-space model for the lithium-ion battery capacity is first constructed to assess capacity degradation. Then, a spherical cubature particle filter (SCPF) is introduced to solve the state-space model. The major idea of the SCPF is to adapt a spherical cubature integration-based Kalman filter to provide an importance function of a standard particle filter (PF). Once the state-space model is determined, the extrapolations of the state-space model to a specified failure threshold are performed to infer the RUL of the lithium-ion batteries. Degradation data of 26 lithium-ion battery capacities were analyzed to validate the effectiveness of the proposed prognostic method. The analytical results show that the proposed prognostic method is more effective in the prediction of RUL of lithium-ion batteries, compared with an existing PF-based prognostic method.