Electrochemical Properties of Na3CoO2 as Positive Electrode Additive for Na-Ion Batteries

摘要

The Na-ion battery(NIB) is one of alternative energy storage devices of lithium-ion batteries (LIB) because of the cost advantage. However, the NIB has lower energy density than the LIB has, which is a critical point that the NIB must overcome to be successfully commercialized. Many research efforts have been made in active electrode materials to improve the energy by increasing capacity. Yet, there is no new electrode materials have been introduced with sufficiently matured. In this work, it is attempted to improve energy density without changing electrode chemistry. Na[3]CoO[2] is synthesized and applied to the positive electrode to compensate the initial irreversible capacity loss by supplying Na-ion from Na[3]CoO[2]. The characteristics of Na[3]CoO[2] as a positive electrode additive were confirmed through the evaluation of physical/electrochemical properties. By applying the Na[3]CoO[2] to positive electrode, the full cell capacity is improved together with stable cycle performance at the same time.