Production of Alkali Sulfide Cathode Materials for Next
Generation Rechargeable Batteries
Xuemin Li, Yongan Yang, and Colin Wolden
Summary: A method to produce hierarchically structured alkali sulfide cathode materials.
Description: Meeting the demands of advanced consumer electronics and electronic vehicles requires next
generation rechargeable batteries with greater specific-energy and energy-density that current lithium ion
batteries. Alkali sulfide (M2S, M = Li and Na) cathodes have great promise for enabling a number of “beyond-
lithium” technologies, including metal-sulfur, graphite-sulfide, and silicone-sulfide batteries. Significant efforts
have been invested to develop M2S cathodes. M2S nanoparticles serve as a good model system as their small
dimensions and high specific surface area enables higher capacity, greater cycling stability, and faster
charging/discharging kinetics, but face the challenge of achieving both high specific-capacity and capacity-density.
In addition the current methods for production of M2S nanoparticles are energy intensive and not viable on a
commercially scale. A number of practical challenges also exist when M2S nanoparticles are directly used in
batteries. M2S hierarchical structures (M2S-HSs) have the potential to overcome many of these limitations. The M2S
hierarchical structures developed in this work are composed of micrometer-sized secondary clusters of M2S
nanoparticles that are wrapped in a carbon scaffolding. These secondary structures have the benefits of both
nanoparticles (improved cyclability and high specific capacity) and of bulk materials (high capacity density). The
secondary structures are wrapped within a carbon-scaffold to form hierarchical structures and electrical
interconnectivity among primary nanoparticles is created producing an effective electrode material.
Main Advantages of this Invention:

The M2S secondary structures are produced through a one-step process, without the need to first
synthesize M2S nanoparticles. The reaction is thermodynamically favorable, spontaneous, rapid, and
complete, and proceeds at room temperature and pressure. The auxiliary reagents can be recycled
without any treatments, enabling a continuous process for manufacturing.

A polymer coating on the secondary structures is applied and is resistant to the solvent used to form the

The carbon scaffold enables electrical interconnectivy among the primary nanoparticles, facilities M-ions
transport throughout the whole structure, and blocks the electrolyte and prevents the formation of
detrimental species inside of the hierarchical structures.

Method completely consumes the reactant H2S, which is a major industrial pollutant.
Potential Areas of Application:


H2S removal
ID number: 16020
Intel ectual Property Status: US provisional patent filed.
Opportunity: We are seeking an exclusive or non-exclusive licensee for implementation of this technology.
For more information contact:
William Vaughan, Director of Technology Transfer
Colorado School of Mines, 1500 Illinois Street, Guggenheim Hall Suite 314, Golden, CO 80401
Phone: 303-384-2555; e-mail: