Novel Organosulfur Cathode Materials for Advanced Lithium Batteries

Michaela Elaine Bell, Purdue University

Abstract

Recent innovations in portable electronics, electric vehicles and power generation by wind and solar have expanded the need for efficient battery storage. Lithium-ion batteries have been the frontline contender of battery storage yet are not able to match current demands. Alternatively, lithium-sulfur batteries are a promising technology to match the consumer demands. Elemental sulfur cathodes incur a variety of problems during cycling including the dissolution of intermediate lithium polysulfides, an undesirable volume change (∼80%) when completely reduced and a high dependence on liquid electrolyte, which quickly degrades the cell's available energy density. Due to these problems, the high theoretical capacity and energy density of lithium sulfur cells are unattainable. In this work, A new class of phenyl polysulfides, C 6H5SxC6H5(4 ≤ x ≤ 6), are developed as liquid sulfur containing cathode materials. This technology was taken a step further to fulfill and emerging need for flexible electronics in technology. Phenyl tetrasulfide ( C6H5SxC6H5) was polymerized to form a high energy density battery with acute mobility. Lithium half-cell testing shows that phenyl hexasulfide (C6H 5SxC6H5) can provide a specific capacity of 650mAh g–1 and capacity retention of 80% through 500 cycles at 1C rate along wit superlative performance up to 10C. Furthermore, 1,302W h kg–1 and 1,720 –1–1 are achievable at a low electrolyte/active material ratio. Electrochemical testing of polymer phenyl tetrasulfide reveals high specific capacities of 634mAh g–1 at 1C while reaching 600mAh g–1 upon mechanical strain testing. This work introduce novel cathode materials for lithium-sulfur batteries and provides a new direction for the development of alternative high-capacity flexible cathode materials.

Degree

M.S.M.E.

Advisors

Fu, Purdue University.

Subject Area

Alternative Energy|Energy

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