Defect-Controlled Formation of Triclinic Na2 CoP2 O7 for 4 V Sodium-Ion Batteries.
Simple defects such as sodium deficiencies can induce the selective synthesis of triclinic Na2 CoP2 O7 , providing an increase in energy density of more than 40 % compared to the stoichiometric polymorph that is preferentially formed under the commonly used synthesis conditions. Such a significant improvement, which was achieved just by changing the crystal structure, suggests that controlling the polymorphism could be an effective and facile method for developing high-performance electrode materials and that defects can play a remarkable role in this process.
Graduate School of EEWS, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.|Suncheon Center, Korea Basic Science Institute, Suncheon, 57922, Republic of Korea.
Heejin
H
Kim
Graduate School of EEWS, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
Chan Sun
CS
Park
Graduate School of EEWS, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea. jangwookchoi@kaist.ac.kr.
Jang Wook
JW
Choi
Graduate School of EEWS, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea. ysjn@kaist.ac.kr.
Yousung
Y
Jung
crystal engineering; density functional calculations; nonstoichiometry; polymorphism; sodium-ion batteries