Superlattice cathodes endow cation and anion co-intercalation for high-energy-density aluminium batteries

Conventionally, rocking-chair batteries capacity primarily depends on cation shuttling. However, intrinsically high-charge-density metal-ions, such as Al³⁺, inevitably cause strong Coulombic ion-lattice interactions, resulting in low practical energy density and inferior long-term stability towards rechargeable aluminium batteries (RABs). Herein, we introduce tunable quantum confinement effects and tailor a family of anion/cation co-(de)intercalation superlattice cathodes, achieving high-voltage anion charge compensation, with extra-capacity, in RABs. The optimized superlattice cathode with adjustable van der Waals not only enables facile traditional cation (de)intercalation, but also activates O^2- compensation with an extra anion reaction. Furthermore, the constructed cathode delivers high energy-density (466 Wh kg^-1 at 107 W kg^-1) and one of the best cycle stability (225 mAh g^-1 over 3000 cycles at 2.0 A g^-1) in RABs. Overall, the anion-involving redox mechanism overcomes the bottlenecks of conventional electrodes, thereby heralding a promising advance in energy-storage-systems.