Advanced Dual-Ion Batteries with High-Capacity Negative Electrodes Incorporating Black Phosphorus

Dual-graphite batteries (DGBs), being an all-graphite-electrode variation of dual-ion batteries (DIBs), have attracted great attention in recent years as a possible low-cost technology for stationary energy storage due to the utilization of inexpensive graphite as a positive electrode (cathode) material. However, DGBs suffer from a low specific energy limited by the capacity of both electrode materials. In this work, a composite of black phosphorus with carbon (BP-C) is introduced as negative electrode (anode) material for DIB full-cells for the first time. The electrochemical behavior of the graphite || BP-C DIB cells is then discussed in the context of DGBs and DIBs using alloying anodes. Mechanistic studies confirm the staging behavior for anion storage in the graphite positive electrode and the formation of lithiated phosphorus alloys in the negative electrode. BP-C containing full-cells demonstrate promising electrochemical performance with specific energies of up to 319 Wh kg^-1 (related to masses of both electrode active materials) or 155 Wh kg^-1 (related to masses of electrode active materials and active salt), and high Coulombic efficiency. This work provides highly relevant insights for the development of advanced high-energy and safe DIBs incorporating BP-C and other high-capacity alloying materials in their anodes.