Affiliation:
1. College of Chemistry and Materials Engineering Wenzhou University Wenzhou 325035 P. R. China
2. Wenzhou Key Laboratory of Sodium‐Ion Batteries Wenzhou University Technology Innovation Institute for Carbon Neutralization Wenzhou 325035 P. R. China
3. College of Science National University of Defense Technology Changsha 410073 P. R. China
4. School of Chemical Engineering & Advanced Materials University of Adelaide Adelaide SA 5005 Australia
Abstract
AbstractAs a typical tunnel oxide, Na0.44MnO2 features excellent electrochemical performance and outstanding structural stability, making it a promising cathode for sodium‐ion batteries (SIBs). However, it suffers from undesirable challenges such as surface residual alkali, multiple voltage plateaus, and low initial charge specific capacity. Herein, an internal and external synergistic modulation strategy is adopted by replacing part of the Mn with Ti to optimize the bulk phase and construct a Ti‐containing epitaxial stabilization layer, resulting in reduced surface residual alkali, excellent Na+ transport kinetics and improved water/air stability. Specifically, the Na0.44Mn0.85Ti0.15O2 using water‐soluble carboxymethyl cellulose as a binder can realize a capacity retention rate of 94.30% after 1,000 cycles at 2C, and excellent stability is further verified in kilogram large‐up applications. In addition, taking advantage of the rich Na content in Prussian blue analog (PBA), PBA‐Na0.44Mn1‐xTixO2 composites are designed to compensate for the insufficient Na in the tunnel oxide and are matched with hard carbon to achieve the preparation of coin full cell and 18650 cylindrical battery with satisfactory electrochemical performance. This work enables the application of tunnel oxides cathode for SIBs in 18650 cylindrical batteries for the first time and promotes the commercialization of SIBs.
Funder
National Natural Science Foundation of China
High-end Foreign Experts Recruitment Plan of China
Key Research and Development Program of Zhejiang Province
Natural Science Foundation of Zhejiang Province
China Scholarship Council
Australian Research Council
Science and Technology Project of State Grid