Nickel ferrite promotes capacity and cycle stability of lithium-sulfur battery

June 13, 2018, Science China Press
Compared to S/CNTs, S/NiFe2O4 has higher volumetric capacity and cycling stability. Credit: ©Science China Press

Lithium-sulfur (Li-S) battery could become practical if 20 percent of the theoretical energy densities (2600 Wh/kg or 2800 Wh/L) can be achieved. Investigators have the ambition to reach energy density of 500 Wh/kg in the near future.

Xue-Ping Gao from Nankai University, says, "Currently, the of 500 Wh/L is not satisfied. But it was already realized in commercial lithium-ion batteries (LIBs) many years ago. The low volumetric energy density is a bottleneck of practical Li-S battery."

Intrinsically, sulfur has lower density than transition metal oxides as cathodes in LIBs. Worse, in order to improve the electrochemical performance, sulfur is usually forced to load onto various lightweight carbon hosts, leading to more lower volumetric of sulfur-based composites, and undermining the volumetric energy density of Li-S battery.

Compared with carbon materials, heavy metal oxides not only offer good adsorption ability of polysulfides to suppress the shuttle effect, but also help to obtain dense sulfur-based composites with high tap density. Gao says, "Based on this, we developed nickel ferrite (NiFe2O4) porous hollow 1-D nanofibers via electrospinning technology. The as-prepared NiFe2O4 nanofibers were used here as a novel host of sulfur in order to increase the volumetric capacity of sulfur-based composites."

Gao details their experiment, "Firstly, the polysulfide adsorption test reveals the strong chemisorption towards soluble polysulfides by NiFe2O4." Both the stable adsorption geometry and adsorption energy of Li2S8 on (111) plane of NiFe2O4 are confirmed by Density Functional Theory (DFT) calculation as compared with carbon nanotubes (CNTs).

As a result, the S/NiFe2O4 composite delivers an initial discharge capacity of 963.6 mAh/g, and good cycle stability. "Furthermore, the S/NiFe2O4 composite shows nearly 2 times higher superior volumetric capacity than S/CNT composite. It comes as no surprise that the S/NiFe2O4 composite has a much larger tap density than the S/CNT composite," he said.

In addition, other metal ferrites MFe2O4 (M = Co, Mg, Zn) have also been investigated as polar hosts of sulfur, and the results confirm the superiority of metal ferrites in fabricating sulfur-based composites with high gravimetric/volumetric capacities for the potential application of Li-S batteries with high gravimetric/volumetric .

Explore further: The ultra-high volumetric energy density lithium-sulfur battery

More information: Ze Zhang et al, Sulfur/nickel ferrite composite as cathode with high-volumetric-capacity for lithium-sulfur battery, Science China Materials (2018). DOI: 10.1007/s40843-018-9292-7

Related Stories

The ultra-high volumetric energy density lithium-sulfur battery

January 23, 2014

Lithium ion battery technology (LIBs) is one of the most important mobile power sources for laptops, cameras, and smart phones. However, the current energy density of LIBs is approaching the theoretical limit, which underscoring ...

Researchers charge ahead to develop better batteries

March 26, 2018

Batteries die at the most inconvenient times. Cellphones go dark during important conversations because a battery hasn't been recharged. Or the automotive industry revs up with excitement for a new battery-powered vehicle, ...

Recommended for you

Collaboration yields discovery of 12-sided silica cages

June 20, 2018

What do you call a materials science discovery that was given a major boost by a lecture from a Nobel laureate in chemistry, used cryogenic electron microscopy (cryo-EM), and was pushed further along by a doctoral student's ...

On the path to an artificial cell

June 20, 2018

It is hoped that cells created in a test tube can answer some of the major questions in biology. What is the minimum that a cell needs in order to live? And how did life on Earth begin? Researchers from the Max Planck Institute ...

Novel genetic method improves efficiency of enzyme

June 20, 2018

Researchers at the U.S. Department of Energy's (DOE's) National Renewable Energy Laboratory (NREL) and the University of Georgia developed a new genetic engineering technique to dramatically improve an enzyme's ability to ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.