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A high-rate and high-efficiency molten-salt sodium–oxygen battery
Energy & Environmental Science ( IF 32.4 ) Pub Date : 2022-09-27 , DOI: 10.1039/d2ee01774a
Yun Guang Zhu 1, 2 , Graham Leverick 1, 3 , Alessandra Accogli 1, 4 , Kiarash Gordiz 1, 3 , Yirui Zhang 1, 3 , Yang Shao-Horn 1, 2, 3, 5
Affiliation  

Alkali metal–oxygen batteries can provide greater specific energy than Li-ion batteries but often suffer from low power density, cycleability, and energy efficiency due to the sluggish kinetics of the oxygen electrode and parasitic reactions at both the oxygen and alkali metal electrodes. In this study, we demonstrated a molten-salt Na–O2 battery operating at 443 K with high areal energy (33 mW h cm−2geo) and power densities (19 mW cm−2geo), with high energy efficiency (∼90% at 5 mA cm−2geo), and stable cycling (400 cycles with no capacity loss). Raman, pressure tracking and titration measurements were used to show that the dominant discharge product is Na2O2. Moreover, the redox activity of nitrate anions in the molten salt was found to be critical to enable the formation of Na2O2. Through 18O-labeling experiments as well as discharging Na–Ar cells, we demonstrated that the discharge reaction occurs via the electrochemical reduction of NaNO3 to Na2O and NaNO2, where chemical reactions with O2 lead to the formation of Na2O2 from Na2O, and the regeneration of NaNO3 from NaNO2.

中文翻译:

一种高倍率高效熔盐钠氧电池

碱金属-氧电池可以提供比锂离子电池更大的比能量,但由于氧电极的动力学缓慢以及氧和碱金属电极的寄生反应,通常会受到低功率密度、循环性和能量效率的影响。在这项研究中,我们展示了一种熔盐 Na-O 2电池,工作温度为 443 K,具有高面能(33 mW h cm -2 geo)和功率密度(19 mW cm -2 geo),具有高能量效率(~在 5 mA cm -2 geo时为 90% ,并且循环稳定(400 次循环,没有容量损失)。拉曼、压力跟踪和滴定测量用于表明主要的放电产物是 Na 2 O2 . 此外,发现熔融盐中硝酸根阴离子的氧化还原活性对于能够形成Na 2 O 2至关重要。通过18 个O 标记实验以及放电 Na-Ar 电池,我们证明了放电反应是通过NaNO 3电化学还原为 Na 2 O 和 NaNO 2发生的,其中与 O 2的化学反应导致 Na 2的形成从 Na 2 O 再生O 2 ,​​从 NaNO 2再生 NaNO 3
更新日期:2022-09-27
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