The High Performance of Crystal Water Containing Manganese Birnessite Cathodes for Magnesium Batteries

详细信息    查看全文

• 作者：Kwan Woo Nam ; Sangryun Kim ; Soyeon Lee ; Michael Salama ; Ivgeni Shterenberg ; Yossi Gofer ; Joo-Seong Kim ; Eunjeong Yang ; Chan Sun Park ; Ju-Sik Kim ; Seok-Soo Lee ; Won-Seok Chang ; Seok-Gwang Doo ; Yong Nam Jo ; Yousung Jung ; Doron Aurbach ; Jang Wook Choi
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：June 10, 2015
• 年：2015
• 卷：15
• 期：6
• 页码：4071-4079
• 全文大小：576K
• ISSN：1530-6992

文摘

Rechargeable magnesium batteries have lately received great attention for large-scale energy storage systems due to their high volumetric capacities, low materials cost, and safe characteristic. However, the bivalency of Mg²⁺ ions has made it challenging to find cathode materials operating at high voltages with decent (de)intercalation kinetics. In an effort to overcome this challenge, we adopt an unconventional approach of engaging crystal water in the layered structure of Birnessite MnO₂ because the crystal water can effectively screen electrostatic interactions between Mg²⁺ ions and the host anions. The crucial role of the crystal water was revealed by directly visualizing its presence and dynamic rearrangement using scanning transmission electron microscopy (STEM). Moreover, the importance of lowering desolvation energy penalty at the cathode鈥揺lectrolyte interface was elucidated by working with water containing nonaqueous electrolytes. In aqueous electrolytes, the decreased interfacial energy penalty by hydration of Mg²⁺ allows Birnessite MnO₂ to achieve a large reversible capacity (231.1 mAh g^鈥?) at high operating voltage (2.8 V vs Mg/Mg²⁺) with excellent cycle life (62.5% retention after 10000 cycles), unveiling the importance of effective charge shielding in the host and facile Mg²⁺ ions transfer through the cathode鈥檚 interface.