Themed collection Rechargeable non-aqueous metal-oxygen batteries

The Faraday Discussion on rechargeable non-aqueous metal–oxygen batteries is summarised.

Here, we discuss experimental approaches developed by some of the authors to understand the function and failure of lithium–oxygen batteries.

The stability of a series of glyme solvents with different chain lengths during ORR/OER has been investigated using in situ vibrational spectroscopy measurements.

We study the competition between the solution route and surface route during the discharging process in Li–O₂ cells.

We explore the role of electrolyte composition in the solvation of I⁻, which has been shown to be critical for the efficient operation of this redox mediator, using a molecular dynamics approach.

A simple goodness of fit R factor to gauge how well a template surface structure can support LiO₂ growth is developed. The R factor may be extended to other transition and main group element LiM_x catalysts, as potential LiO₂ growth supports.

The ratio of electrolyte amount against areal capacity (E/C) has a large impact on the performance of stacked-type lithium–oxygen batteries. The unique cell degradation behavior during the charging process under low E/C conditions was also demonstrated.

Solid-state Li–O₂ battery, 3D architecture and cycling performance.

We consider the requirements to be placed on an electrolyte for it be used in a practical lithium–air battery. Ways to ease these requirements by refining cell design and improving transport as well as motifs for future electrolytes are discussed.

A Li–air battery is described with in-line gas handling that allows control over the flow and composition of the gas supplied to the cell, allowing simultaneous evaluation of the cell and scrubber performance.

A low-barrier, two-step reaction pathway for peroxide-based K–O chemistry is first realized without any catalysts under the inert argon atmosphere.

The effect of Group 1 alkali-metal cations (Na⁺, K⁺, and Cs⁺) on the oxygen reduction and evolution reactions (ORR and OER) using dimethyl sulfoxide (DMSO)-based electrolytes was investigated.

Rechargeable metal–air batteries operated in ambient air fail as a result of complex anode surface reactions. Interphases composed of metallic In protect Li anodes, enabling Li–air batteries to operate in ambient air.

We examine the build-up and distribution of Li₂CO₃ within the porous gas diffusion electrode during cycling and its link to cell failure.

The reaction pathway for Li₂O generation on the surface of perovskite LaNi_0.5Co_0.5O₃ for a molten-salt lithium–oxygen battery operating at 160 °C is presented.

A considerable performance gap between Li symmetric cells and practical Li batteries motivated us to explore the correlation between the shape of voltage traces and degradation.

Calculated interface between Li₂O and Li₂O₂ surfaces showing the extent of disorder at the interface. Such interfaces are probably present in the new solid-state Li–air battery described here and contribute to the discharge and charge mechanisms.

This study demonstrates that the stability of cycling in situ Li anodes depends on their depth of discharge (DOD). High DOD cycling results in unstable performance due to the accumulation of interfacial degradation at Li/LLZO interfaces.

A green, low-toxic diglyme isomer, 1,2,3-trimethoxypropane, has been studied, for the first time, as the electrolyte in sodium–air batteries reaching 2.31 mA h cm⁻² discharge capacity and with NaO₂ as the main discharge product.

We have shown direct spectroscopic evidence of the previously identified pathways for singlet oxygen (¹O₂) formation in non-aqueous oxygen redox chemistry.

We have operando detected the formation of singlet oxygen in a real Li–O₂ battery by DMA fluorescence decay and its suppression by using physical quenchers, reaching an extended battery cycle life due to mitigation of spurious reactions

This work identifies the key products and intermediates (O₂⁻, KO₂ and K₂O₂) and reveals their dependency on the electrode potential by combining in situ Raman spectroelectrochemistry and density functional theory calculations.