Chemical/electrochemical corrosion behaviors of advanced current collector materials for aqueous zinc metal pouch cells

Aqueous zinc metal batteries (AZMBs) have triggered tremendous research interest in large-scale energy storage systems due to the advantages of resource abundance, low cost and environmentally friendly. Current collectors play significant roles in enhancing the electrochemical performance of AZMBs, especially aqueous zinc metal pouch cells (AZMPCs). However, the influence of the carbon or metal based current collectors on the performance of AZMPCs has rarely been investigated. This work comprehensively studies the chemical and electrochemical corrosion behaviors of graphite felt (GF), nickel foam (Ni) and stainless steel (SS) as current collectors in AZMPCs for the first time to identify the optimal candidate. The 3D porous GF collector with chemical inertness exhibits excellent chemical corrosion resistance under 2 M ZnSO 4  + 0.2 M MnSO 4 aqueous electrolyte by immersion testing for 30 days. In addition, linear sweep voltammetry and chronoamperometry results demonstrate that GF has high electrochemical stability, which is beneficial to the inhibition of swelling and active materials shedding in pouch cells. In contrast, 2D SS and Ni collectors displays severe structural damage along with surface corrosion after cycling for 100 cycles in AZMPCs. This phenomenon could be ascribed to the intrinsic high activity of metal and formation of corrosion layer under high electrolyte content. Lastly, the corrosion behavior of SS from button cells to pouch cells has been investigated to reveal the rigorous requirements of the latter on current collectors in terms of chemical/electrochemical corrosion resistance and electrochemical stability. This work provides guidance for the development of advanced current collectors for AZMPCs.