Dual-ion batteries: The emerging alternative rechargeable batteries

Development of energy storage technologies is thriving because of the increasing demand for renewable and sustainable energy sources. Although lithium-ion batteries (LIBs) are already mature technologies that play important roles in modern society, the scarcity of cobalt and lithium sources in the Earth's crust limits their future deployment at the scale required to supplant fossil fuels. Dual-ion batteries (DIBs) based on a different combination of chemistries are emerging-energy storage-systems. Conventional DIBs apply the graphite as both electrodes and a combination of organic solvents and lithium salts as electrolytes. This configuration is fascinating because of its high working potential (>4.5 V vs. Li/Li+), potentially high energy density, high safety and low cost. But it also accompanies some negative issues like limited capacity of intercalation-type graphite electrodes, cyclic stability endangered by large anions intercalation and solvent co-intercalation and electrolyte decomposition under high voltage. This review aims at pointing out the challenges in the current work on DIBs with subcategories of positive and negative electrodes (cathode and anode), and electrolytes and comparing the strategies for improvements with better fundamental understanding of DIBs.