Self-standing porous carbon electrodes for lithium-oxygen batteries under lean electrolyte and high areal capacity conditions

Abstract

The theoretical energy densities of lithium-oxygen batteries (LOBs) surpass those of lithium-ion batteries (LiBs). However, most of the LOBs reported contain excess electrolyte amounts and operate under low areal capacity conditions thereby exhibiting a cell-level energy density much lower than that of the LiBs. In the present study, we prepared a series of carbon powder-based self-standing membranes with different pore structures and investigated their battery performance under low electrolyte/areal capacity (E/C < 10 g A−1 h−1) conditions. Although, a clear correlation was observed between the total discharge capacity and pore volume of the carbon electrodes, the cycle number of the LOBs did not simply correlate with the total discharge capacity of the carbon electrodes. In particular, the carbon electrode mainly composed of mesopores exhibited superior cycle performance under low E/C conditions (E/C < 5 g A−1 h−1). We believe that the results obtained in this study show a new direction for the material design of porous carbon electrodes to realize LOBs with practically high energy density and long cycle life.