Monday, 14 May 2018
Ballroom 6ABC (Washington State Convention Center)
2D layered metal chalcogenides have displayed extraordinary properties that have put them on the forefront of various applications as promising catalysts, sensors, electrochromic devices, and electric actuators. Specifically, metal chalcogenides such as titanium (IV) sulfide (TiS2), has been identified as a promising low cost cathode for rechargeable batteries. TiS2 can exhibit specific capacities with a completely lithium-intercalated LixTiS2 (x = 1) as high as 238 mAhg-1. The electrochemical performance of bulk TiS2 cathodes has been hindered by its low ion diffusion coefficient and moderate electrical conductivity. To overcome these challenges, bulk TiS2 cathodes are mixed with conductive additives (typically carbon) and polymer binders (typically polyvinylidene fluoride -PVDF) to yield a paste that is finally cast onto a current collector. However, the electrochemical performance of the electrode is lowered due to the extra weight of all the inactive components (i.e., additives, polymer binder, and metal substrates) introduced during the fabrication. An alternative to the use of pasted electrodes is the direct growth of well-defined nanostructures on a conducting substrate. In this work, we report the synthesis, characterization, and electrochemical performance of carbon- and binder-free cathodes comprised of highly conducting TiS2 nanobelts. The short ion diffusion paths, high electrical conductivity and absence of materials that hinder ion migration such as carbon and PVDF have led to Li-ion and Na-ion batteries exhibiting high capacity, less capacity fade, and resilience under higher cycling rates. Moreover, key to developing new secondary battery systems is multielectron reactions involving more than one electron transfer, which may lead to higher specific capacity and energy density. Herein, we will discuss our recent findings towards rechargeable aluminum batteries comprising carbon- and binder-free TiS2 cathode electrodes. Finally, we will also discuss preliminary results that demonstrate high electrochemical performance of carbon- and binder-free TiS2 electrodes in all-solid state ion batteries.