This paper summarizes the many different materials that have been studied and used as the current collectors of positive electrodes for lithium-based batteries. Aluminum is by far the most common of these and a detailed literature exists, examining the stability in many different electrolytes. Depending on the salts and additives, different types of protective film are formed. The solubility of these films in the electrolyte is thought to be a determining factor in the overall stability of the current collector. However, various other materials, not all of which form a protective layer, have found application in particular systems.

Deep eutectic electrolytes have recently been considered as alternatives to classical room-temperature ionic liquids. This work is an initial study of the zinc deposition process from a basic choline chloride/ethylene glycol deep eutectic solvent containing <mml:math display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>ZnCl</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>ZnCl2 at <mml:math display="inline"><mml:mrow><mml:mn>30</mml:mn><mml:mo>°</mml:mo><mml:mi mathvariant="normal">C</mml:mi></mml:mrow></mml:math>30°C . The system was examined by cyclic voltammetry at static and rotating glassy carbon disk electrodes and by potential step techniques. There was little deposition initially on sweeping or stepping the potential to −0.5 to −0.8 V vs Zn/Zn(II), but more rapid deposition was observed when the potential was subsequently raised to −0.4 to −0.2 V. The role of choline chloride was also studied by comparing with a choline-free electrolyte, which exhibited a more conventional voltammetric response. The formation of a dissolved, intermediate species <mml:math display="inline"><mml:mi>Z</mml:mi></mml:math>Z on the cathodic sweep was proposed to account for the observed deposition behavior in the deep eutectic. Furthermore, an observation of the electrodeposition behavior with the addition of sodium ethoxide supports the suggestion that <mml:math display="inline"><mml:mi>Z</mml:mi></mml:math>Z is a complex of <mml:math display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mtext>Zn</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>Zn2+ and deprotonated components of the solvent.

Mesoporous metallic tin has been electrodeposited, from the homogeneous hexagonal mesophase of a series of amphiphilic non-ionic surfactants, with a controllable repeat structure in the range of 5–10 nm.