A highly stable zinc anode protected by a corrosion inhibitor for seawater-based zinc-ion batteries

The island-based energy storage is of urgent need for the grid construction combined with renewable energy for offshore operation. The direct use of seawater as a substitute of deionized water shows its great promise for aqueous zinc-ion batteries in such a specific situation. However, the metal corrosion, dendrite growth, and hydrogen evolution stand out in the harsh seawater environment. To address these challenges, we proposed a corrosion inhibitor that was effective in the field of metal anti-corrosion, 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA), to inhibit anode corrosion caused by Cl– and active H2O molecules by forming a stable solid electrolyte interphase (SEI) film in the seawater-based electrolyte. Besides, PBTCA can chelate with other cations present in seawater, such as Ca2+ and Mg2+, thereby preventing the aggregation and precipitation of sparingly soluble species. Under a current density of 5 mA cm−2, the seawater-based zinc-ion battery exhibited an exceptional cycle life exceeding 2000 h and maintained a Coulombic efficiency of over 99.6% after 2000 cycles. Additionally, the performance of the Zn||ZVO full battery was significantly enhanced with the addition of PBTCA. This study provides a simple, low-cost, and efficient approach for making the seawater-based zinc-ion batteries useable.