Boosting Proton Conductivity in Highly Robust 3D Inorganic Cationic Extended Frameworks through Ion Exchange with Dihydrogen Phosphate Anions.
The limited long-term hydrolytic stability of rapidly emerging 3D-extended framework materials (MOFs, COFs, MOPs, etc.) is still one of major barriers for their practical applications as new solid-state electrolytes in fuel cells. To obtain hydrolytically stable materials, two H2 PO4 (-) -exchanged 3D inorganic cationic extended frameworks (CEFs) were successfully prepared by a facile anion-exchange method. Both anion-exchanged CEFs (YbO(OH)P and NDTBP) show significantly enhanced proton conductivity when compared with the original materials (YbO(OH)Cl and NDTB) with an increase of up to four orders-of-magnitude, reaching 2.36×10(-3) and 1.96×10(-2)  S cm(-1) at 98 % RH and 85 °C for YbO(OH)P and NDTBP, respectively. These values are comparable to the most efficient proton-conducting MOFs. In addition, these two anion-exchanged materials are stable in boiling water, which originates from the strong electrostatic interaction between the H2 PO4 (-) anion and the cationic host framework, showing a clear advance over all the acid-impregnated materials (H2 SO4 @MIL-101, H3 PO4 @MIL-101, and H3 PO4 @Tp-Azo) as practical solid-state fuel-cell electrolytes. This work offers a new general and efficient approach to functionalize 3D-extended frameworks through an anion-exchange process and achieves water-stability with ultra-high proton conductivity above 10(-2)  S cm(-1) .
School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher, Education Institutions, Soochow University, 199 Ren'ai Road, Suzhou 215123 (China).
Chengliang
C
Xiao
School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher, Education Institutions, Soochow University, 199 Ren'ai Road, Suzhou 215123 (China).
Yaxing
Y
Wang
School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher, Education Institutions, Soochow University, 199 Ren'ai Road, Suzhou 215123 (China).
Lanhua
L
Chen
School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher, Education Institutions, Soochow University, 199 Ren'ai Road, Suzhou 215123 (China).
Xuemiao
X
Yin
Analysis and Testing Center, Soochow University, 199 Ren'ai Road, Suzhou 215123 (China).
Jie
J
Shu
School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher, Education Institutions, Soochow University, 199 Ren'ai Road, Suzhou 215123 (China).
Daopeng
D
Sheng
School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher, Education Institutions, Soochow University, 199 Ren'ai Road, Suzhou 215123 (China).
Zhifang
Z
Chai
Department of Chemistry and Biochemistry, Florida State University, 95 Chieftain Way, Tallahassee, Florida 32306 (United States).
Thomas E
TE
Albrecht-Schmitt
School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher, Education Institutions, Soochow University, 199 Ren'ai Road, Suzhou 215123 (China). shuaowang@suda.edu.cn.
Shuao
S
Wang
anion exchange; cationic extended frameworks; dihydrogen phosphate; proton conduction; water stable