Sodium (Na) ion batteries are attracting increasing attention for use in various electrical applications. However, the electrochemical behaviors, particularly the working voltages, of Na ion batteries are substantially lower than those of lithium (Li) ion batteries. Worse, the state‐of‐the‐art Na ion battery cannot meet the demand of miniaturized in modern electronics. Here, we demonstrate that electrochemically exfoliated graphene (EG) nanosheets can reversibly store (PF₆⁻) anions, yielding high charging and discharging voltages of 4.7 and 4.3 V vs. Na⁺/Na, respectively. The dual‐graphene rechargeable Na battery fabricated using EG as both the positive and negative electrodes provided the highest operating voltage among all Na ion full cells reported to date, together with a maximum energy density of 250 Wh kg⁻¹. Notably, the dual‐graphene rechargeable Na microbattery exhibited an areal capacity of 35 μAh cm⁻² with stable cycling behavior. This study offers an efficient option for the development of novel rechargeable microbatteries with ultra‐high operating voltage and high energy density.

中文翻译：

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双石墨烯可充电钠电池

钠（Na）离子电池在各种电气应用中的使用引起了越来越多的关注。然而，Na离子电池的电化学行为，特别是工作电压，显着低于锂（Li）离子电池的电化学行为。更糟糕的是，最先进的钠离子电池无法满足现代电子产品中小型化的需求。在这里，我们表明，电化学剥离的石墨烯（EG）纳米片可以可逆地吸留（PF ₆ ^- ）的阴离子，得到高的充电和4.7放电电压和4.3 V，相对于钠⁺/ Na。使用EG作为正极和负极制造的双石墨烯可充电Na电池在迄今为止报道的所有Na离子全电池中提供了最高的工作电压，并且最大能量密度为250 Wh kg ^-1。值得注意的是，双石墨烯可充电Na微型电池的面积容量为35μAhcm ^-2，具有稳定的循环行为。这项研究为开发具有超高工作电压和高能量密度的新型可充电微型电池提供了有效的选择。