Progress towards aluminum-ion batteries

Compared to conventional lithium-ion batteries, aluminum-ion batteries (AIBs) offer significant advantages, such as non-flammability, and a high capacity of the metallic Al anode. However, due to inadequate cathodic performance, especially capacity, high-rate capability and cycle life, AlBs cannot compete with Li-ion batteries and supercapacitors. The energy density of AIBs (40–60 Wh/kg) is much lower than that of commercialized Li-ion batteries (150–250 Wh/kg), and AlBs’ power density (3–30 kW/kg) and cycle life (200–25,000 cycles) are lower than those of advanced supercapacitors (30–100 kW/kg and 10,000–100,000 cycles). The following four basic requirements should be fulfilled simultaneously for a desired carbon-based cathode: 1) Highly crystallized defect-free graphene lattice as an active anion intercalation site affording suitable energy storage capacities; 2) Continuous electron-conducting matrix for large current transport and internal polarization mitigation; 3) High mechanical strength and Young’s modulus to prevent material collapsing during repeated anion intercalation and de-intercalation; and 4) Interconnected channels facilitating high electrolyte permeability, ion diffusion and fast redox reactions between…