Alkaline ion-solvating membranes combine the high ion conductivity of aqueous hydroxide solutions with the good gas barriers characteristics of the polymer phase, which makes it an attractive polymer electrolyte system for the next generation alkaline water electrolyzers. Membranes based on polybenzimidazole (PBI) show remarkably high ion conductivity that far exceeds 100 mS cm -1 in 20-30 wt.% KOH, which allows for operation at current densities exceeding 2000 mA cm -2 at <1.9 V when combined with highly active electrodes. However, the stability of the most common PBI derivative, poly(2,2´-(m-phenylene)-5,5′bibenzimidazole) (m-PBI), is limited due to gradual backbone degradation, which results in severe membrane degradation within months under simulated operating conditions and weeks during electrolysis tests. Recent studies and simulations on model systems have revealed that the chemical degradation occurs through nucleophilic attack at the C2 position of neutral benzimidazole units, leading to ring opening and subsequent amide hydrolysis. Despite efforts to improve stability through mechanical reinforcement, blending with more chemically stable components, or lowering the KOH concentration, these approaches are not presenting a solution to the intrinsic stability limitations of m-PBI. Therefore, alternative PBI chemistries and other polymers based on poly(arylene ether sulfone), perfluorosulfonate, imidazole functionalized poly(arylene alkylene), poly(vinyl alcohol), styrene-ethylene-butylene copolymers and poly(oxindole biphenylene) have been explored with the aim of mitigating backbone degradation.