High-Energy Density Li-Ion Battery Cathode Using Only Industrial Elements.

Li-ion batteries are crucial for the global energy transition to renewables; however, their scalability is limited by the supply of key elements used in commercial cathodes (e.g., Ni, Mn, Co, P).

Cation Vacancies Enable Anion Redox in Li Cathodes.

Conventional Li-ion battery intercalation cathodes leverage charge compensation that is formally associated with redox on the transition metal. Employing the anions in the charge compensation mechanism, so-called anion redox, can yield higher capacities beyond the traditional limitations of intercalation chemistry. Here, we aim to understand the structural considerations that enable anion oxidation and focus on processes that result in structural changes, such as the formation of persulfide bonds.

Reducing Voltage Hysteresis in Li-Rich Sulfide Cathodes by Incorporation of Mn.

Conventional intercalation-based cathode materials in Li-ion batteries are based on charge compensation of the redox-active cation and can only intercalate one mole of electron per formula unit. Anion redox, which employs the anion sublattice to compensate charge, is a promising way to achieve multielectron cathode materials. Most anion redox materials still face the problems of slow kinetics and large voltage hysteresis.

Effect of Polysulfide Speciation on Mg Anode Passivation in Mg-S Batteries.

Mg-S batteries are a promising next-generation system for beyond conventional Li-ion chemistry. The Mg-S architecture pairs a Mg metal anode with an inexpensive, high-capacity S cathode. However, S-based cathodes exhibit the "polysulfide shuttle" effect, wherein soluble partially reduced S species generated at the cathode diffuse to and react with the anode.

Mg Anode Passivation Caused by the Reaction of Dissolved Sulfur in Mg-S Batteries.

As Li-ion battery optimization approaches theoretical limits, interest has grown in designing next-generation batteries from low-cost earth-abundant materials. Mg-S batteries are promising candidates, exhibiting widespread abundance of elemental precursors and a relatively large theoretical energy density albeit at lower cell voltage. However, Mg-S batteries exhibit poor reversibility, in part due to interactions between dissolved polysulfides and the Mg anode.