energy, [4] large scale and portable energy storage becomes increasingly more important. Therefore, continued research into high-performing alternatives, which will meet the increased demand is imperative. A common way of evaluating potential alternatives for Li-based batteries involves calculating the theoretical specific capacity of potential candidates and comparing these results with other figures of merit. This reasoning leads to the conclusion that metals in the upper left corner of the periodic table are more interesting than the others. Table 1 shows these calculations together with some other parameters for common metal anodes.A second important parameter when searching for potential battery materials is the oxidation potential of the anode, where lower (less noble) is better. Comparing these parameters for the metals listed in Table 1 shows immediately that Li is one of the most promising candidates, but rare. The second most promising metal is aluminium (Al), which has a relatively high standard oxidation potential. Heavier metals and those in higher groups show much worse performance indicators. Nevertheless, this method of evaluation has to be considered with caution, because it is based on numerous assumptions. Such as, that the anode is oxidized during the charging/discharging process, which is not true for many practical systems.The literature on non-Li based intercalation batteries is clearly dominated by sodium (Na), [9,10] magnesium (Mg) [11,12] and Al [13] systems that are all more abundant natural elements than Li. There are few examples of potassium (K) [14] and (Ca), [15] which coincides clearly with the trend observed in Table 1 (as mentioned above, low performing "candidates" have been omitted in this table). Great efforts are aimed at these alternatives to improve capacity, power and cycles. Comparing Na-ion with Li-ion batteries, the common feature is a monovalent ion that can be inserted/extracted into/from the electrode material. Here, only one charge transfer takes place in contrast to Mg-ion, Ca-ion or Al-ion where two and three charges are involved in redox reactions respectively. As a result of multielectron reactions, higher specific capacity and energy density may be obtained. A key issue in order for multivalent ion insertion to be feasible is the electrode material that has to allow ion mobility.In this review, electrode materials for Al-ion batteries, namely different cathodes are discussed. Furthermore, their performance is compared highlighting drawbacks and advantages of every material.Over the last decade, optimizing energy storage has become significantly important in the field of energy conversion and sustainability. As a result of immense progress in the field, cost-effective and high performance batteries are imperative to meeting the future demand of sustainability. Currently, the best performing batteries are lithium-ion based, but limited lithium (Li) resources make research into alternatives essential. In recent years, the performance of aluminium-ion batteries ha...