Computational investigation of MAX as intercalation host for rechargeable aluminum-ion battery

Layered carbides and their analogs with MAX phase (general formula AMn+1Xn) have emerged as promising candidates for energy storage and conversion applications. One frontier for energy storage is using MAX as an Al-ion intercalation electrode. Given that many MAXs have their A sites being Al, the structure can potentially serve as a stable host for Al intercalation. Here in this work, we computationally enumerated 425 ternary MAX Al-ion battery electrodes. Specifically, we perform first principal phase diagram calculations on the combinatorial space of 17 types of typical transition metals, 5 types of anions (C, N, B, Si, P), three types of stoichiometries (n=1, 2, 3) and two types of layered stackings (α and β). Among all the ternary MAX materials, 44 candidates show reasonable synthetic accessibility and 5 shows extraordinary performance than most reported Al-ion battery electrodes. With the phase stability, electrochemical performance (average voltage, theoretical capacity, energy density and Al diffusion barrier), our work provide comprehensive computational assessment of the great opportunities behind MAX based Al-ion battery.