Carbon Gel-Based Self-Standing Membranes as the Positive Electrodes of Lithium–Oxygen Batteries under Lean-Electrolyte and High-Areal-Capacity Conditions

Abstract

Lithium−oxygen batteries (LOBs) are promising nextgeneration rechargeable batteries due to their high theoretical energy densities. The optimization of the porous carbon-based positive electrode is a crucial challenge in the practical implementation of LOB technologies. Although numerous studies have been conducted regarding the relationships between LOB performance and the physicochemical properties of carbon electrodes, most of these studies evaluate the performances of the electrodes under unrealistic conditions with inappropriate technological parameters. In this study, we prepared carbon gel-based self-standing membranes as positive electrodes and evaluated their performances in LOBs under lean-electrolyte, high-areal-capacity conditions. We clarified the following three crucial points: (1) The nanometer-sized pores exhibited limited effects in improving the cycle performance, although they contributed in enhancing the discharge capacity. (2) The macro-sized pores displayed positive effects in enhancing the discharge capacity. (3) The crystallinity and/or surface functional groups influence the discharge potential and cycle life. The results of this study suggest the significance of controlling the physicochemical properties of a porous carbon-based positive electrode in preparing a LOB with a practically high energy density and an extended cycle life.

Hierarchical porous-structured self-standing carbon nanotube electrode for high-power lithium–oxygen batteries

“…Therefore, to prevent the undesired aggregation of the CNTs, we focused on the nonsolvent-induced phase separation technique (NIPS). 3,12,13 In the NIPS process, the membrane was formed from a slurry using a doctor blade. The wetted membrane was placed in an ethanol (EtOH) bath and the solvent was exchanged thrice to completely replace the NMP with EtOH.…”

Rechargeable Lithium-Air Batteries with Practically High Energy Density

“…3 Notably, when a carbon-black-based self-standing membrane was used as the positive electrode in an LAB, the cell exhibited a capacity of >7000 mAh/g electrode at a current density of 0.4 mA/cm 2 . In addition, the method developed for preparing selfstanding carbon membrane was also applicable to various carbon materials, 10,11 revealing the novelty of the proposed method.…”

Research and Development of Novel Secondary Batteries in Japan

“…While promising, these approaches suffer from several fundamental and technical problems. The VSI reports significant achievements for the Mg-metal batteries in developing new electrolytes and electrode active materials through collaboration between material scientists and computational scientists in Japan. − The VSI describes extensive studies on the elucidating mechanisms of oxygen electrode reaction, developing electrode materials and solvents, and establishing cell design strategies for the practical implementation of Li–O 2 batteries. − …”