Two-Dimensional GeP3 as a High Capacity Anode Material for Non-Lithium-Ion Batteries

Utilization of non-lithium-ion batteries in next generation renewable energy storage is hindered by the lack of appropriate electrode materials with desired electrochemical performance. Motivated by low peeling-off energy (Ding et al. Nano Lett. 2017, 17(3), 1833-1838), an experimentally available two-dimensional material, nominated as GeP3, is investigated as the anode for non-lithium-ion batteries (Na+, Ca2+, Mg2+, Al3+) based on density functional theory calculations. The electrochemical properties, i.e., ion intercalation mechanism, diffusion behavior, and theoretical capacities of different metal ions in GeP3, are systematically investigated. A semiconductor-to-metal transition and improved conductivity are observed due to ions intercalation in the GeP3 electrode. Even though the charge storage mechanism of Na and Ca ions is quite different, the GeP3 monolayer has exhibited a high theoretical capacity of 1295.42 mAh g(-1) for both Na+ and Ca2+ ions. Furthermore, collective Na ions transport at the phase boundary indicates that the sodiated GeP3 electrode favors well-distributed phase formation instead of separation or clustering at the nanoscale, which is beneficial in avoiding the thermal runaway issues induced by dendrite formation. Moreover, the shallow and steady intercalation/deintercalation resistance of the Na ion at the dilute limit and phase boundary in GeP3 suggests excellent rate performance and high cyclic stability. These results provide a steady path toward further development and utilization of two-dimensional GeP3 as an anode in non-lithium-ion batteries.