No abstract

Light weight carbon nanofibers (CNF) fabricated by a simple electrospinning method and used as a 3D structured current collector for a sulfur cathode. Along with a light weight, this 3D current collector allowed us to accommodate a higher amount of sulfur composite, which led to a remarkable increase of the electrode capacity from 200 to 500 mAh per 1 g of the electrode including the mass of the current collector. Varying the electrospinning solution concentration enabled obtaining carbonized nanofibers of uniform structure and controllable diameter from several hundred nanometers to several micrometers. The electrochemical performance of the cathode deposited on carbonized PAN nanofibers at 800 °C was investigated. An initial specific capacity of 1620 mAh g−1 was achieved with a carbonized PAN nanofiber (cPAN) current collector. It exhibited stable cycling over 100 cycles maintaining a reversible capacity of 1104 mAh g−1 at the 100th cycle, while the same composite on the Al foil delivered only 872 mAh g−1. At the same time, 3D structured CNFs with a highly developed surface have a very low areal density of 0.85 mg cm−2 (thickness of ~25 µm), which is lower for almost ten times than the commercial Al current collector with the same thickness (7.33 mg cm−2).

This research aimed to increase the mass loading of sulfur in the composite electrode in order to increase the energy density of the lithium-sulfur (Li-S) cell. This requires designing the electrode with the use of conductive agents to maintain the conductivity of the sulfur composite. Therefore, the composite of sulfur with polyacrylonitrile (PAN) and carbon nanotubes (CNT) was synthesized by heating. Following that, the mass loading of sulfur was increased by using several layers of carbon fiber paper (CFP) with a large free space as a three-dimensional current collector. As a result of the heat treatment and formation of covalent bonding between pyrolyzed PAN and sulfur, uniform distribution and enhanced conductivity were achieved, while CNT maintained structural integrity, acting as an interwoven network. Due to these advantages, the mass loading of sulfur was increased up to 5 mg cm −2 while maintaining a high initial specific capacity of 1400 mAh g −1 and stable cyclability.

No abstract

Ni@NGC with different contents of Ni coated onto the surface of commercial separators effectively suppresses the polysulfide shuttle effect and enhances the electrochemical reaction kinetics and overall performance of a Li–S battery.