Anomalously High Lithium Storage in Three-Dimensional Graphene-like Ordered Microporous Carbon Electrodes

Zeolitelated carbon, having a three-dimensional graphene-like ordered microporous structure with high electrical conductivity, is a fascinating anode material for Li-ion batteries (LIBs). Herein, we report an extremely high Li capacity of 2950 mA h g^-1 (equivalent to Li_1.3/C), which is 7.9 times the maximum capacity of graphite, Li/C₆. This is equivalent to the crowded packing of 20 Li⁺ per pore with 0.9 nm diameter. Approximately 59% of the capacity was reversible. According to the characterizations by electron energy loss spectroscopy, ⁷Li NMR, and ¹³C NMR, most of the Li species existed as Li⁺ within the carbon micropores. Contrary to the often-made assumption, only a small amount of solid-electrolyte interphase layers was detected at the external surface of the carbon particles but not inside the micropores. The anomalously high Li capacity is attributed to the extremely narrow pore environment, where Li⁺ would be difficult to be fully solvated. Tailoring of the carbon pores to a subnanometric range would therefore be exciting for future advancement of LIBs.