Anode-Electrolyte Interfaces in Secondary Magnesium Batteries

Abstract

Secondary magnesium batteries are still in the research stage, after the first prototype of a magnesium-based battery was demonstrated almost two decades ago. Since this breakthrough, despite tremendous efforts by numerous research groups, we are not aware of any system that exhibits better performance in terms of Coulombic efficiency over prolonged cycling. The scientific community is now focusing on the basic phenomena that hinder development of practical magnesium-based rechargeable batteries. Today, we have a better understanding of the structure of electrolyte solutions relevant to rechargeable Mg batteries and its effect on the electrochemical performance. New electrolyte solutions that are not based on organometallic moieties currently surpass the performance of the first generations of complex solutions. There is even an attempt to test alternative anode materials for magnesium-based energy storage systems. In this review, we summarize recent studies conducted in the field, with a focus on the anode/electrolyte solutions side.

A Stable Solid Electrolyte Interphase for Magnesium Metal Anode Evolved from a Bulky Anion Lithium Salt

“…These observations have challenged the long‐held passivation mechanism of Mg/electrolyte interface and verified the possibility of forming SEI on Mg anode surface by some delicate surface modifications. However, there is few report about the direct reduction of Mg electrolyte components for in situ forming an Mg 2+ ‐conducting SEI on Mg anode surface …”

Rechargeable Magnesium–Sulfur Battery Technology: State of the Art and Key Challenges

“…Interface issues concerning the electrodes in Mg–S batteries and those in their analogous Li–S batteries are quite different . In Li–S batteries, the lithium polysulfides are formed and dissolved in the electrolyte solution and then further reduced to insoluble Li 2 S at the Li anode, where a so‐called solid electrolyte interphase (SEI) forms, whose composition is crucial for cell performance.…”

A Trip to Oz and a Peak Behind the Curtain of Magnesium Batteries

“…A number of recent reviews provide a detailed account of the major strides that have been made to‐date on magnesium electrolytes. [ 2,9,13,14,17,41 ] The purpose of this section is to recap the highlights in magnesium electrolyte research and suggest a direction for future research. Reversible plating and stripping of magnesium can be achieved using Grignard reagents in ethereal solvents as an electrolyte but unfortunately such electrolytes have low voltage stability (i.e., < 1.5 V vs Mg/Mg 2+ ) and are therefore impractical.…”

“…There have been numerous reviews that have provided in‐depth discussions on the status of rechargeable magnesium batteries. [ 2,9–17 ] In this report, we challenge the community to come to terms with the reality of what is possible with magnesium batteries and provide some direction for future magnesium battery research. We hope this report will spur controversy and redirect the community to answer crucial questions regarding the negative electrodes, positive electrodes, and electrolytes.…”