HIGH-CAPACITY ANODE MATERIALS FOR SODIUM ION BATTERIES

摘要

Thanks to the low cost of Na precursors and the abundant Na resources, Na-ion batteries have been considered a promising alternative to Li-ion batteries for large-scale energy storage systems. However, the cost decrease of Na-ion batteries relative to that of Li-ion batteries cannot be easily achieved, in spite of the inexpensive Na precursors. Since Na-ion batteries have slightly lower energy densities than Li-ion batteries, the energy density limitations offset the cost savings due to the use of Na. Accordingly, the cost per energy ($/Wh) of Na-ion batteries can be decreased only when the similar energy density of Na-ion batteries to that of Li-ion batteries is obtained. The energy density of Na-ion batteries can be improved by using high-capacity anode materials with appropriately low redox potentials (about <0.4 V vs. Na/Na~+). Therefore, in this presentation, we introduce high-capacity anode materials such as phosphorus and tin phosphide in order to improve the energy density of Na-ion batteries (Figure 1).