Two-dimensional materials represent a promising material platform for next-generation energy storage and conversion devices. Owing to their advantageous features of large surface area, widely open ion transport pathway within 2D layers, and mechanical flexibility, graphene and other transition-metal oxides and phosphates based nanosheet materials show great promise in next-generation high-density energy storage devices. Here we will present examples on inorganic 2D materials and their hybrids for advanced energy storage devices including alkali-ion batteries and supercapacitors. The first set of examples is inorganic VOPO₄ ultrathin nanosheets for ultraflexible solid-state supercapacitors, as well as for both Li-ion and Na-ion storage. And we will also discuss a novel synthetic strategy towards controlled synthesis of porous inorganic nanosheet materials as a promising class of alkali-ion battery electrodes with high capacity and rate capability.