Through the Maze of Multivalent‐Ion Batteries: A Critical Review on the Status of the Research on Cathode Materials for Mg²⁺ and Ca²⁺ Ions Insertion

Abstract

This review aims to address the status of transition metal‐based cathode materials for Mg2+ and Ca2+‐based multivalent‐ion batteries on a critical standpoint, providing a comprehensive overview. Multivalent‐based ions battery (MIB) technologies are among the most promising post‐lithium electrochemical energy storage devices currently studied, but they still fall short in several aspects due to their early stage of research. In addition, difficult experimental conditions related to the electrolyte systems and the cathode materials require an additional quote of care when performing experiments. In this review, a global approach is undertaken, from an introduction to electrolytes to the studied insertion parameters that allow a fast (de)insertion of multivalent ions. Then, the currently studied structural classes of cathode materials and a critical comment on data reporting, which are among the focal points of the actual state‐of‐the‐art research, are thoroughly discussed.

Energy Storage Mechanism, Challenge and Design Strategies of Metal Sulfides for Rechargeable Sodium/Potassium‐Ion Batteries

“…[ 2 ] However, LIBs are trapped by scarce reserves (≈0.0017 wt%), high costs and safety issues. [ 3 ] Therefore, it is urgent to develop novel generation EES devices, [ 4 ] such as sodium‐ion batteries (SIBs), [ 5 ] potassium‐ion batteries (PIBs), [ 6 ] zinc‐ion batteries (ZIBs), [ 7 ] magnesium‐ion batteries (MIBs), [ 8 ] calcium‐ion batteries (CIBs), [ 9 ] aluminum‐ion batteries (AIBs), [ 10 ] dual‐ion batteries (DIBs), [ 11 ] and solid‐state batteries (SSBs), [ 12 ] etc.…”

Revisiting the chevrel phase: Impact of dispersion corrections on the properties of Mo6S8 for cathode applications

“…Hence, alternative battery concepts and new battery materials are needed which allow for sustainable, safe, compact and high voltage energy storage systemsl. 4,5 While it seems unlikely that alternative battery technologies will be able to surpass Li in the area of portable batteries, there is also a growing demand for stationary energy storage and heavy-duty systems. The requirements of those can, on the other hand, be met by different battery types.…”

“…Multivalent batteries suffer from mobility issues due to the higher ionic charge 5,[9][10][11][12] and also typically exhibit lower operating voltages than LIBs. 7 Additionally, new battery chemistries typically also require the identification and/or development of suitable electrolytes and electrode materials.…”

“…7 Additionally, new battery chemistries typically also require the identification and/or development of suitable electrolytes and electrode materials. 5 Being a very abundant metal that can be sourced locally in many countries, makes Mg a promising candidate among the different possibilities for multivalent charge carriers. [13][14][15][16] Because of its abundance and low toxicity, it is a viable option for a green and sustainable battery material, moreover offering a high volumetric capacity (3833 mAh • cm −3 as compared to 2061 mAh • cm −3 in the case of Li).…”

“…Although there has been increased research interest in Mg batteries, problems with respect to electrolyte stability at the anode and the rather low operating voltage still need to be solved. 5 As a common problem, the insertion of Mg ions on the cathode side is often sluggish and hard to reverse, which is mainly due to the divalent ions being strongly bound at the cathode side. 17 Multiple cathode materials have been proposed for Mg batteries such as spinels, 18 V 2 O 5 19 or the chevrel phase (CP) [13][14][15][16] .…”