The O3-type lithium transition metal oxides, LiMeO 2, have been intensively studied as positive electrode materials for lithium batteries, and O3-LiCoO 2, 10 Li [Ni 0.8 Co 0.15 Al 0.05 ]O 2, 26, 27 and Li [Ni 1/3 Mn 1/3 Co 1/3] O 2 28, 29 are often utilized for practical Li-ion batteries.
Moreover, the recent achievements in nanostructured positive electrode materials for some of the latest emerging rechargeable batteries are also summarized, such as Zn-ion batteries, F- and Cl-ion batteries, Na–, K– and Al–S batteries, Na– and K–O 2 batteries, Li–CO 2 batteries, novel Zn–air batteries, and hybrid redox flow batteries.
Recent progress in multivalent metal (Mg, Zn, Ca, and Al) and metal-ion rechargeable batteries with organic materials as promising electrodes. Small 15, 1805061 (2019). Kim, D. J. et al. Rechargeable aluminium organic batteries. Nat. Energy 4, 51–59 (2019).
These future rechargeable battery systems may offer increased energy densities, reduced cost, and more environmental benignity. A particular focus is directed to the design principles of these nanostructured positive electrode materials and how nanostructuring influences electrochemical performance.
Although organic compounds have already shown great potential for application in Al-ion batteries by virtue of their intrinsic merits, the research on organic positive electrodes for Al-ion batteries is still in a primary stage. There are numerous research topics for further enhancement of organic materials for Al-ion batteries.
Nanotechnology has opened up new frontiers in materials science and engineering in the past several decades. Considerable efforts on nanostructured electrode materials have been made in recent years to fulfill the future requirements of electrochemical energy storage. Compared to bulk materials, most of thes