Selenium-Doped Cathodes for Lithium-Organosulfur Batteries with Greatly Improved Volumetric Capacity and Coulombic Efficiency

Jinqiu Zhou; Tao Qian; Na Xu; Mengfan Wang; Xuyan Ni; Xuejun Liu; Xiaowei Shen; Chenglin Yan

doi:10.1002/adma.201701294

Selenium-Doped Cathodes for Lithium-Organosulfur Batteries with Greatly Improved Volumetric Capacity and Coulombic Efficiency

Adv Mater. 2017 Sep;29(33). doi: 10.1002/adma.201701294. Epub 2017 Jul 10.

Authors

Jinqiu Zhou^{1

2}, Tao Qian^{1

2}, Na Xu^{1

2}, Mengfan Wang^{1

2}, Xuyan Ni^{1

2}, Xuejun Liu^{1

2}, Xiaowei Shen^{1

2}, Chenglin Yan^{1

2}

Affiliations

¹ Soochow Institute for Energy and Materials InnovationS, College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, 215006, China.
² Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University, Suzhou, 215006, China.

PMID: 28691212
DOI: 10.1002/adma.201701294

Abstract

For the first time a new strategy is reported to improve the volumetric capacity and Coulombic efficiency by selenium doping for lithium-organosulfur batteries. Selenium-doped cathodes with four sulfur atoms and one selenium atom (as the doped heteroatom) in the confined structure are designed and synthesized; this structure exhibits greatly improved volumetric/areal capacities, and a Coulombic efficiency of almost 100% for highly stable lithium-organosulfur batteries. The doping of Se significantly enhances the electronic conductivity of battery electrodes by a factor of 6.2 compared to pure sulfur electrodes, and completely restricts the production of long-chain lithium polysulfides. This allows achievement of a high gravimetric capacity of 700 mAh g^-1 close to its theoretical mass capacity, an exceptional volumetric capacity of 2457 mAh cm^-3 , and excellent capacity retention of 92% after 400 cycles. Shuttle effect is efficiently weakened since no long-chain polysulfides are detected from in situ UV/vis results throughout the entire cycling process arising from selenium doping, which is theoretically confirmed by density functional theory calculations.

Keywords: Coulombic efficiency; Se doping; lithium-organosulfur batteries; shuttle effect; volumetric capacity.