Lum Yan Wei

Cathode design for lithium-sulfur batteries

Lithium–sulfur (Li–S) batteries are considered to be one of the most viable options for next-generation high-energy rechargeable batteries. Li–S batteries can deliver a practical energy density of 400–600 W h kg, which is 2–3 times as high as that of commercially available Li-ion batteries. However, during discharge the sulfur cathode converts into soluble polysulfides, which can diffuse to the lithium anode where irreversible chemical reactions can occur (polysulfide shuttle mechanism). I designed a novel sulfur-carbon yolk-shell, whereby the carbon shell serves to confine polysulfides, thereby enabling reversible charging and discharging of a Li-S battery.

Functional anode interphases by magnesium batteries

Magnesium (Mg) batteries are another promising option for higher capacity and safer batteries. However, the reactive nature of Mg means that often, passivating films that inhibit ionic conduction tend to form on the Mg anode. This inhibits reversible plating and stripping of the Mg anode, thus preventing charging/discharging. I work on designing functional Mg anode interphases, which have high Mg ionic conductivity, enabling low overpotential plating and stripping. This is achieved by addition of electrolyte additives to form this artificial solid-electrolyte interphase (SEI).