S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Chemical and Biological Engineering (화학생물공학부) Journal Papers (저널논문_화학생물공학부)
Anomalous Manganese Activation of a Pyrophosphate Cathode in Sodium Ion Batteries: A Combined Experimental and Theoretical Study
- Park, Chan Sun; Kim, Heejin; Shakoor, Rana A.; Yang, Eunjeong; Lim, Soo Yeon; Kahraman, Ramazan; Jung, Yousung; Choi, Jang Wook
- Issue Date
- Journal of the American Chemical Society, Vol.135 No.7, pp.2787-2792
- Sodium ion batteries (SIBs) have many advantages such as the low price and abundance of sodium raw materials that are suitable for large-scale energy storage applications. Herein, we report an Mn-based pyrophosphate, Na2MnP2O7, as a new SIB cathode material. Unlike most Mn-based cathode materials, which suffer severely from sluggish kinetics, Na2MnP2O7 exhibits good electrochemical activity at similar to 3.8 V vs Na/Na+ with a reversible capacity of 90 mAh g(-1) at room temperature. It also shows an excellent cycling and rate performance: 96% capacity retention after 30 cycles and 70% capacity retention at a c-rate increase from 0.05C to 1C. These electrochemical activities of the Mn-containing cathode material even at room temperature with relatively large particle sizes are remarkable considering an almost complete inactivity of the Li counterpart, Li2MnP2O7. Using first-principles calculations, we find that the significantly enhanced kinetics of Na2MnP2O7 is mainly due to the locally flexible accommodation of Jahn-Teller distortions aided by the corner-sharing crystal structure in triclinic Na2MnP2O7. By contrast, in monoclinic Li2MnP2O7, the edge-sharing geometry causes multiple bonds to be broken and formed during charging reaction with a large degree of atomic rearrangements. We expect that the similar computational strategy to analyze the atomic rearrangements can be used to predict the kinetics behavior when exploring new cathode candidates.
- Files in This Item: There are no files associated with this item.