Browsing by Author "Dirican, Mahmut"

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Citation - WoS: 28
Citation - Scopus: 30
Centrifugally-Spun Carbon Microfibers and Porous Carbon Microfibers as Anode Materials for Sodium-Ion Batteries
(Elsevier Science Bv, 2016) Dirican, Mahmut; Zhang, Xiangwu
Natural abundance and low cost of sodium resources bring forward the sodium-ion batteries as a promising alternative to widely-used lithium-ion batteries. However, insufficient energy density and low cycling stability of current sodium-ion batteries hinder their practical use for next-generation smart power grid and stationary storage applications. Electrospun carbon microfibers have recently been introduced as a high-performance anode material for sodium-ion batteries. However, electrospinning is not feasible for mass production of carbon microfibers due to its complex processing condition, low production rate and high cost. Herein, we report centrifugal spinning, a high-rate and low-cost micro fiber production method, as an alternative approach to electrospinning for carbon microfiber production and introduce centrifugally-spun carbon microfibers (CMFs) and porous carbon microfibers (PCMFs) as anode materials for sodium-ion batteries. Electrochemical performance results indicated that the highly porous nature of centrifugally-spun PCMFs led to increased Na+ storage capacity and improved cycling stability. The reversible capacity of centrifugally-spun PCMF anodes at the 200th cycle was 242 mAh g(-1) which was much higher than that of centrifugally-spun CMFs (143 mAh g(-1)). The capacity retention and coulombic efficiency of the centrifugally-spun PCMF anodes were 89.0% and 99.9%, respectively, even at the 200th cycle. (C) 2016 Elsevier B.V. All rights reserved.
Citation - WoS: 14
Citation - Scopus: 18
Fabrication and Electrochemical Behavior Study of Nano-Fibrous Sodium Titanate Composite
(Elsevier Science Bv, 2017) Ge, Yeqian; Zhu, Jiadeng; Dirican, Mahmut; Jia, Hao; Yanilmaz, Meltem; Lu, Yao; Zhang, Xiangwu
Nanofiber structured Na2Ti3O7 was synthesized via electrospinning process which was further used as an anode material for sodium-ion batteries for the first time. One-dimensional construction of Na2Ti3O7 composite could contribute to better electrochemical activity. It was demonstrated that the capacity of Na2Ti3O7 nanofibers was significantly improved to 257.8 mAh g(-1) at 30 mA g(-1). Furthermore, the rate capability of Na2Ti3O7 nanofibers was significantly enhanced, showing charge capacities were 161.8, 116.5, and 72.4 mAh g(-1) at 100, 200, and 400 mA g(-1), respectively. Therefore, improved specific capacity and rate capability made Na2Ti3O7 nanofibers composite as a promising anode material for sodium-ion batteries.