The application of energy storage device is sharply expanding its application area from small portable mobile devices to large-scale energy storage systems (ESS). The cost of energy storage device has become more important as the demand of large-scale device expands. The outstanding performance such as large energy density of lithium ion battery (LIB) makes itself a most powerful energy storage device. However, LIB has some growing concerns about cost due to its limited reserves of raw materials. For large-scale ESS, alternative energy storage system other than LIB with low price and moderate performance is required. There have been extensive studies on various types of energy storage devices meet these demands, and sodium ion battery (SIB) is one of the most promising candidate. Sodium ion, which is an alkaline metal, has similar characteristics with lithium ion even though it is earth abundant metal. Researchers have started the sodium ion battery study by focusing on these similarities and the main purpose of this study is to develop the post-LIB with low cost. The main difference between sodium and lithium ion is potential difference ((E⁰_Na/Na+=-2.71 V and E⁰_Li/Li+=-3.04 V) and ionic radius. Many materials have been studied for SIB electrode, but only a few materials achieve a certain level of performance even though those candidate materials show good lithium ion storage performance. The ionic radius difference between sodium and lithium ion is thought to be main cause of this phenomena. Especially in case of anode, the graphite was most powerful LIB anode material with low price and good performance but graphite has very low capacity with sodium ion. So there are many efforts to develop SIB anode to achieve similar performance level graphite of LIB. The main advantage of SIB is a low cost, therefore the research of SIB anode should be conducted with considering the price efficiency. To meet this point, the anode of SIB should be developed with carbon material, which has low price of raw material.

In this presentation, the fabrication of disordered carbon with mechanical method for SIB anode will be reported. The facile and cost-effective mechanical milling process can make high quality disordered carbon and it has good sodium ion storage performance. The sodium ion storage mechanism of mechanically milled disordered carbon also will be presented. The details will be discussed at the meeting.