Despite their exceptionally high capacity, overlithiated layered oxides (OLO) have not yet been practically used in lithium-ion battery cathodes due to necessary toxic/complex chemical activation processes and unsatisfactory electrochemical reliability. Here, a new class of ecofriendly chemical activation strategy based on amphiphilic deoxyribose nucleic acid (DNA)-wrapped multiwalled carbon nanotubes (MWCNT) is demonstrated. Hydrophobic aromatic bases of DNA have a good affinity for MWCNT via noncovalent π–π stacking interactions, resulting in core (MWCNT)-shell (DNA) hybrids (i.e., DNA@MWCNT) featuring the predominant presence of hydrophilic phosphate groups (coupled with Na+) in their outmost layers. Such spatially rearranged Na+–phosphate complexes of the DNA@MWCNT efficiently extract Li+ from monoclinic Li2MnO3 of the OLO through cation exchange reaction of Na+–Li+, thereby forming Li4Mn5O12-type spinel nanolayers on the OLO surface. The newly formed spinel nanolayers play a crucial role in improving the structural stability of the OLO and suppressing interfacial side reactions with liquid electrolytes, eventually providing significant improvements in the charge/discharge kinetics, cyclability, and thermal stability. This beneficial effect of the DNA@MWCNT-mediated chemical activation is comprehensively elucidated by an in-depth structural/electrochemical characterization.
Bibliographical noteFunding Information:
J.-M.K., J.-H.P., and E.J. contributed equally to this work. This work was supported by U.S. Army Research Office (ARO) (Grant No. W911NF-18-1-0016), Basic Science Research Program (Grant No. 2018R1A2A1A05019733), and Wearable Platform Materials Technology Center (Grant No. 2016R1A5A1009926) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT, and future Planning. This work was also supported by the Korea Forest Research Institute (Grant No. FP 0400-2016-01) and Batteries R&D of LG Chem. The work done at KIST was supported by the Technology Development Program to Solve Climate Changes of the National Research Foundation (NRF) funded by the Ministry of Science & ICT (Grant Number: 2017M1A2A2044482) and KIST Institutional Program (Project No. 2E30212).
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)