title: The High Performance of Crystal Water Containing Manganese Birnessite Cathodes for Magnesium Batteries.
abstract: 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 Mg(2+) 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 Mg(2+) 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-electrolyte interface was elucidated by working with water containing nonaqueous electrolytes. In aqueous electrolytes, the decreased interfacial energy penalty by hydration of Mg(2+) allows Birnessite MnO2 to achieve a large reversible capacity (231.1 mAh g(-1)) at high operating voltage (2.8 V vs Mg/Mg(2+)) with excellent cycle life (62.5% retention after 10000 cycles), unveiling the importance of effective charge shielding in the host and facile Mg(2+) ions transfer through the cathode's interface.
authors.affiliation: †Graduate School of Energy, Environment, Water, and Sustainability (EEWS) and KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Kwan Woo
authors.initials: KW
authors.lastname: Nam
authors.affiliation: †Graduate School of Energy, Environment, Water, and Sustainability (EEWS) and KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Sangryun
authors.initials: S
authors.lastname: Kim
authors.affiliation: ‡Department of Electronic Chemistry, Tokyo Institute of Technology, 4259 G1-1 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan.
authors.forename: Soyeon
authors.initials: S
authors.lastname: Lee
authors.affiliation: §Department of Chemistry and Bar-Ilan Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Salama
authors.affiliation: §Department of Chemistry and Bar-Ilan Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel.
authors.forename: Ivgeni
authors.initials: I
authors.lastname: Shterenberg
authors.affiliation: §Department of Chemistry and Bar-Ilan Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel.
authors.forename: Yossi
authors.initials: Y
authors.lastname: Gofer
authors.affiliation: †Graduate School of Energy, Environment, Water, and Sustainability (EEWS) and KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Joo-Seong
authors.initials: JS
authors.lastname: Kim
authors.affiliation: †Graduate School of Energy, Environment, Water, and Sustainability (EEWS) and KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Eunjeong
authors.initials: E
authors.lastname: Yang
authors.affiliation: †Graduate School of Energy, Environment, Water, and Sustainability (EEWS) and KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Chan Sun
authors.initials: CS
authors.lastname: Park
authors.affiliation: ∥Energy Lab., Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803, Republic of Korea.
authors.forename: Ju-Sik
authors.initials: JS
authors.lastname: Kim
authors.affiliation: ∥Energy Lab., Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803, Republic of Korea.
authors.forename: Seok-Soo
authors.initials: SS
authors.lastname: Lee
authors.affiliation: ∥Energy Lab., Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803, Republic of Korea.
authors.forename: Won-Seok
authors.initials: WS
authors.lastname: Chang
authors.affiliation: ∥Energy Lab., Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803, Republic of Korea.
authors.forename: Seok-Gwang
authors.initials: SG
authors.lastname: Doo
authors.affiliation: ⊥Advanced Batteries Research Center, Korea Electronics Technology Institute (KETI), #25, Saenari-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 463-816, Republic of Korea.
authors.forename: Yong Nam
authors.initials: YN
authors.lastname: Jo
authors.affiliation: †Graduate School of Energy, Environment, Water, and Sustainability (EEWS) and KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Yousung
authors.initials: Y
authors.lastname: Jung
authors.affiliation: §Department of Chemistry and Bar-Ilan Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel.
authors.forename: Doron
authors.initials: D
authors.lastname: Aurbach
authors.affiliation: †Graduate School of Energy, Environment, Water, and Sustainability (EEWS) and KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Jang Wook
authors.initials: JW
authors.lastname: Choi
keywords: Birnessite; Magnesium batteries; aqueous batteries; charge screening; crystal water