The Role of the Carbon Framework in Sulfur-Carbon Composite Cathodes in Li-S Batteries

Park

Bulletin Korean Chem Soc

et al. 2019

Self Cite

We present an innovative Li S battery concept for the potential realization of low-cost wearable batteries. A novel Li S battery is constructed by employing a sulfur-free carbon cathode and a sulfur-layered separator fabricated by thermal evaporation at a temperature as low as 120 C. The cell exhibits superior performances compared with a control cell with a sulfur-containing cathode, as all sulfur on the separator takes part in the electrochemical reactions. We reveal that all electrically isolated sulfur from the carbon cathode is successfully converted to polysulfides via the electrode reactions of sulfur molecules at the interface of the carbon surface and the electrolyte solution. Our new concept brings a paradigm shift in the rechargeable battery community.

Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

A Sulfur‐layered Separator Enabling an Innovative Flexible LiS Battery without Integrating Elemental Sulfur in the Cathode

Park

Bulletin Korean Chem Soc

et al. 2019

Self Cite

“…In other words, the insulating nature of sulfur does not inhibit the regular operation of LiS cells. In addition, we have shown that the improved performance of C/S composites is closely related to the ability of the porous carbon framework to absorb polysulfides …”

Section: Introductionmentioning

confidence: 99%

A Novel Design of Sulfur Cathode Integrating a Sulfur Film on a Carbon Electrode for a Low‐Cost and Facile Fabrication of Sustainable LiS Cells

Bulletin Korean Chem Soc

et al. 2019

Self Cite

We present a sulfur-layered carbon electrode, a new configuration of sulfur cathode, which is constructed by a two-step slurry-casting process. The Li S cells employing the new sulfur cathode normally operate with large capacities. Sulfur particles on the carbon layer are not visible upon discharging to 2.1 V in the first discharge, indicating that electrically isolated sulfur is participated in the electrochemical reactions at the carbon surface. This strategy will bring about a paradigm shift in the design of high-performance sulfur cathodes and open new perspectives in the low-cost manufacturing of sustainable Li S cells.

ACS Appl. Mater. Interfaces

“…Moreover, the destructible electrode structure encounters a big challenge for realizing a high-performance sulfur cathode with high areal sulfur loading, which has a vital practical significance for the full cell system. The low electronic conductivity of the sulfur species further aggravates the situation. − …”

Section: Introductionmentioning

confidence: 99%

Biomimetic Root-like TiN/C@S Nanofiber as a Freestanding Cathode with High Sulfur Loading for Lithium–Sulfur Batteries

Liao

Xiang

Yuan

et al. 2018

It is a tough issue to achieve high electrochemical performance and high sulfur loading simultaneously, which is of important significance for practical Li–S batteries applications. Inspired by the transportation system of the plant root in nature, a biomimetic root-like carbon/titanium nitride (TiN/C) composite nanofiber is designed as a freestanding current collector for the high sulfur loading cathode. Like the plant root which absorbs water and oxygen from soil and transfers them to the trunk and branches, the root-like TiN/C matrix provides high-efficiency polysulfide, electron, and electrolyte transfer for the redox reactions via its three-dimensional-porous interconnected structure. In the meantime, TiN can not only anchor the polysulfides via the polar Ti–S and N–S bond but also further facilitate the redox reaction because of its high catalytic effect. With 4 mg cm–2 sulfur loading, the TiN/C@S cathode delivers a high initial discharge capacity of 983 mA h g–1 at 0.2 C current density; after 300 charge/discharge cycles, the discharge capacity remains 685 mA h g–1, corresponding to a capacity decay rate of ∼0.1%. Even when the sulfur loading is increased to 10.5 mg cm–2, the cell still delivers a high capacity of 790 mA h g–1 and a decent cycle life. We believe that this novel biomimetic root-like structure can provide some inspiration for the rational structure design of the high-energy lithium–sulfur batteries and other composite electrode materials.