Hollow V 2 O 5 nanospheres wrapped by activated carbon to confine polysulfides for lithium sulfur battery
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ORIGINAL PAPER
Hollow V2O5 nanospheres wrapped by activated carbon to confine polysulfides for lithium sulfur battery Cheng Liu 1 & Meng Xiang 1 & Jianrong Xiao 1,2 & Songshan Ma 2 & Yaping Zeng 1 & Xinyu Li 1 & Heng Wang 1 Received: 27 May 2020 / Revised: 13 July 2020 / Accepted: 27 July 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The practical application of the Li-S battery is restrained by the severe lithium polysulfide shuttle and sulfur insulation. In this work, the hollow V2O5 nanospheres wrapped by activated carbon as the host material for sulfur were prepared. The results indicate that initial specific discharge capacity of the electrode is 972 mA h g−1 and it can be maintained at 730 mA h g−1 after 200 cycles at 0.2 C. The average decay rate of the capacity for the AC@V2O5/S only is 0.09% per cycle after 200 cycles at 0.5 C. This excellent performance could result from the polar hollow V2O5 nanospheres providing more adsorption sites, which are conducive to electrolyte diffusion and confine polysulfides during the reaction of sulfur and polysulfide. Furthermore, the activated carbon coated on the outer layer can provide the large specific surface as conductive network. Therefore, this design strategy could show significant prospects for Li-S battery. Keywords Li-S battery . Hollow V2O5 nanospheres . Activated carbon . Polysulfides confine
Introduction Traditional lithium batteries using transition metal oxides such as LiCoO2, LiMn2O4, and LiNiO2 as cathode materials have been unable to satisfy the needs of overall development, especially for the higher specific capacity and higher energy density [1, 2]. The high theoretical specific capacity (1675 mA h g−1) and energy density (2600 w h kg−1) of lithium sulfur (Li-S) batteries have been attracted [3–5]. In addition, the cathode sulfur presents advantages of low cost, abundant reserves and nontoxicity compared with the transition metal [6–10]. The commercial application is still limited though its enormous potential. These challenges are containing (1) the polysulfide Li2Sn (4 < n < 8) diffused and dissolved * Jianrong Xiao [email protected] * Xinyu Li [email protected] * Heng Wang [email protected] 1
College of Science, Guilin University of Technology, Guilin 541004, People’s Republic of China
2
School of Physics and Electronics, Central South University, Changsha 410083, People’s Republic of China
seriously caused by shuttle effect and (2) sulfur volume change arising from the (de)lithiation process [10–13]. Especially, the shuttle effect will lead to low coulombic efficiency, severe capacity decay, and poor cycle stability. In order to overcome these challenges, researchers have made tremendous efforts that hold sulfur and polysulfides by designing a variety of host materials. The sulfur host material should contain these functions for Li-S batteries: (1) adsorption capacity for lithium polysulfides, (2) excellent electrical conductivity, and (3) lessen the sulfur volume expansion [14, 15]. In the past few years, inc
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