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Ngoc Thi Bao Nguyen,Hoang Van Nguyen,Nhan Thanh Tran,Phat Tan Vu,Phung My Loan Le,Man Van Tran 대한금속·재료학회 2023 ELECTRONIC MATERIALS LETTERS Vol.19 No.3
High voltage cathode materials LiNi x Mn 2−x O 4 (x = 0.4; 0.5) have been attracting greater attention in developing high energydensity Li-ion battery technology for electrical vehicles and large-scale applications. The main challenge of high voltagecathodes is severe electrolyte decomposition leading to short cell cycle life. In addition, LiNi 0.4 Mn 1.6 O 4 cathode materialprocessed with polyvinylidene fl uoride (PVdF) binder generally suff ers an oxidation decomposition as well as cathodedelamination from current collectors during cycling. Herein, we suggest using sodium carboxymethyl cellulose (CMC),lithium polyacrylic acid (LiPAA) as water-soluble binders for replacing conventional PVdF in cathode processing to demonstratethe eff ectiveness on long-cycling of half-cell Li || LiNi 0.4 Mn 1.6 O 4 , full-cell SiO 2 -graphite || LiNi 0.4 Mn 1.6 O 4 and SiO 2|| LiNi 0.4 Mn 1.6 O 4 . In half-cell, the cells with water-soluble binders-based cathode exhibited a higher discharge capacity thanthe one using PVdF binder (CMC—126.0 mAh/g; LiPAA—125.7 mAh/g; PVdF—117 mAh/g at C/5, respectively). CMCand LiPAA also improve retention capacity up to 90% after 500 cycles at C/3. Interestingly, LiPAA based electrode exhibitsan excellent rate-capability with discharge capacity of 80 mAh/g at 8C. The stability of electrodes was also investigated byelectrode chemical impedance spectroscopy (EIS) and Scanning electron microscope (SEM). In full-cell, CMC and LiPAAbased cells showed eff ectiveness in decreasing transition metal dissolution and preventing the cathode degradation duringlong-cycling through its excellent capacity retention in 200 cycles at C/3.
Nguyen Van Hieu,Le Thi Ngoc Loan,Nguyen Duc Khoang,Nguyen Tuan Minh,Do Thanh Viet,Do Cong Minh,Tran Trung,Nguyen Duc Chien 한국물리학회 2010 Current Applied Physics Vol.10 No.2
In this paper, a very simple procedure was presented for the reproducible synthesis of large-area SnO2nanowires (NWs) on a silicon substrate by evaporating Sn powders at temperatures of 700, 750, and 800 ℃. As-obtained SnO2 NWs were characterized by field emission scanning electron microscopy (FESEM),transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy. They revealed that the morphology of the NWs is affected by growth temperature and the SnO2 NWs are single-crystalline tetragonal. The band gap of the NWs is in the range of 4.2–4.3 eV as determined from UV/visible absorption. The NWs show stable photoluminescence with an emission peak centered at around 620 nm at room-temperature. The sensors fabricated from the SnO2 NWs synthesized at 700 ℃ exhibited good response to LPG (liquefied petroleum gas) at an operating temperature of 400 ℃.