Vertically Aligned Binder-Free TiO2 Nanotube Arrays Doped with Fe, S and Fe-S for Li-ion Batteries

Abstract

Vertically aligned Fe, S, and Fe-S doped anatase TiO2 nanotube arrays are prepared by an electrochemical anodization process using an organic electrolyte in which lactic acid is added as an additive. In the electrolyte, highly ordered TiO2 nanotube layers with greater thickness of 12 μm, inner diameter of approx. 90 nm and outer diameter of approx. 170 nm are successfully obtained. Doping of Fe, S, and Fe-S via simple wet impregnation method substituted Ti and O sites with Fe and S, which leads to enhance the rate performance at high discharge C-rates. Discharge capacities of TiO2 tubes increased from 0.13 mAh cm−2(bare) to 0.28 mAh cm−2 for Fe-S doped TiO2 at 0.5 C after 100 cycles with exceptional capacity retention of 85 % after 100 cycles. Owing to the enhancement of thermodynamic and kinetic properties by doping of Fe-S, Li-diffusion increased resulting in remarkable discharge capacities of 0.27 mAh cm−2 and 0.16 mAh cm−2 at 10 C, and 30 C, respectively.

Free-standing TiO2nanograssy tubular hybrid membrane for polysulfide trapping in Li–S battery

“…Anodization was carried out in a two-electrode cell: a degreased Ti foil with a diameter of Ø 19 mm was cut into pieces and welded with the Ti metal current connector for electrical connection as a working electrode and platinum mesh is used as a counter electrode in a high-voltage potentiostat (ODA, OPS-22101, Incheon, Korea) by applying a ramped voltage of 60 V at 1 V s −1 for 4 hours in an organic electrolyte of ethylene glycol + 0.5 wt% NH 4 F + 1 vol% H 2 O. 25,31 Aer anodization, the sample was rinsed and soaked in ethanol for 10 minutes then nally dried at room temperature. To convert the 'as-prepared' layer into anatase TiO 2 ; the sample was annealed at 450 °C in the air for 1 hour at a heating rate of 15 °C min −1 using a rapid thermal annealer.…”

“…Moreover, there are also reports addressing the use of anodic TiO 2 nanotube layers in conventional Li-ion batteries. 25,[29][30][31][32][33][34][35]40,41 These applications are commonly based on the use of TiO 2 nanotubular structures along with a titanium metal substrate as an electrode. Until now, there is ambiguity on the direct application of such freestanding membrane 38 in Li-ion batteries.…”

Infiltration -driven performance enhancement of poly-crystalline cathodes in all-solid-state batteries

“…Electronic devices such as the internet of things (IoT), wearable devices, and electric vehicles (EVs) require safe lithium-ion batteries (LIBs) with a high energy density that can be rapidly charged. Therefore, for the development of EVs that can be driven for long distances, several recent studies have focused on alternative battery technologies such as lithium-sulfur batteries [1][2][3][4] with a high theoretical capacity and highenergy-density nickel-rich layered oxide cathodes [5][6][7] . Commercial LIBs containing liquid electrolytes comprising flammable organic components are unsafe and often catch fire or explode, as highlighted by numerous incidents involving fires in EVs and smartphones.…”

Improvements in the Magnesium Ion Transport Properties of Graphene/CNT‐Wrapped TiO2‐B Nanoflowers by Nickel Doping

“…Recently, many theories and experiments have proved that doping TiO 2 with metal (such as Zn 2+ and Fe 3+ ) or non-metal (N 3− , F − , and S 2− ) can produce anionic or cationic defects to change the band gap, and ultimately achieve the purpose of improving the electrical conductivity of TiO 2 itself. [17,[40][41][42][43] Opra et al found that TiO 2 creates oxygen vacancy after Zn 2+ doping, which is conducive to improving the electrical conductivity of TiO 2 . [44] By adding Zn element as a dopant to TiO 2 -B, the band gap of the electrode material has been lowered from 3.28 to 3.21 eV, thereby enhancing its electrochemical performance.…”