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.

Effect of Metal Band Position on Anion Redox in Alkali-Rich Sulfides.

New energy storage methods are emerging to increase the energy density of state-of-the-art battery systems beyond conventional intercalation electrode materials. For instance, employing anion redox can yield higher capacities compared with transition metal redox alone. Anion redox in sulfides has been recognized since the early days of rechargeable battery research.

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.

Water Vapor Induced Superionic Conductivity in ZnPS.

Next-generation batteries based on sustainable multivalent working ions, such as Mg, Ca, or Zn, have the potential to improve the performance, safety, and capacity of current battery systems. Development of such multivalent ion batteries is hindered by a lack of understanding of multivalent ionics in solids, which is crucial for many aspects of battery operation. For instance, multivalent ionic transport was assumed to be correlated with electronic transport; however, we have previously shown that Zn can conduct in electronically insulating ZnPS with a low activation energy of 350 meV, albeit with low ionic conductivity.

Six-month sustained delivery of anti-VEGF from in-situ forming hydrogel in the suprachoroidal space.

Patients with wet age-related macular degeneration (AMD) require intravitreal injections of bevacizumab (Bev) or other drugs, often on a monthly basis, which is a burden on the healthcare system. Here, we developed an in-situ forming hydrogel comprised of Bev and hyaluronic acid (HA) crosslinked with poly(ethylene glycol) diacrylate for slow release of Bev after injection into the suprachoroidal space (SCS) of the eye using a microneedle. Liquid Bev formulations were cleared from SCS within 5 days, even when formulated with high viscosity, unless Bev was conjugated to a high molecular-weight HA (2.

An Exploration of Sulfur Redox in Lithium Battery Cathodes.

Secondary Li-ion batteries have enabled a world of portable electronics and electrification of personal and commercial transportation. However, the charge storage capacity of conventional intercalation cathodes is reaching the theoretical limit set by the stoichiometry of Li in the fully lithiated structure. Increasing the Li:transition metal ratio and consequently involving structural anions in the charge compensation, a mechanism termed anion redox, is a viable method to improve storage capacities.

Activating Magnesium Electrolytes through Chemical Generation of Free Chloride and Removal of Trace Water.

Mg batteries are attractive next-generation energy storage systems due to their high natural abundance, inexpensive cost, and high theoretical capacity compared to conventional Li-ion based systems. The high energy density is achieved by electrodeposition and stripping of a Mg metal anode and requires the development of effective electrolytes enabled by a mechanistic understanding of the charge-transfer mechanism. The magnesium aluminum chloride complex (MACC) electrolyte is a good model system to study the mechanism as the solution phase speciation is known.

Conditioning-Free Mg Electrolyte by the Minor Addition of Mg(HMDS).

Mg-based batteries are an attractive next-generation energy storage chemistry due to the high natural abundance and inexpensive cost of Mg, along with the high theoretical energy density compared to that of conventional Li-ion chemistry. The greater energy density is predicated on a Mg metal anode, and pathways to achieving reversible Mg electrodeposition and stripping are reliant on the development of Mg electrolytes. Although Mg electrolyte chemistry has advanced significantly from the reactive Grignards of the 1920s to the carboranes of this decade, there remains significant challenges in correlating the Mg metal anode electrochemistry with the composition of the electrolyte salts as a result of the complicated interface of Mg metal and the electrolyte.