Boron-doped sodium layered oxide for reversible oxygen redox reaction in Na-ion battery cathodes.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34489437.
- Also identified by DOI 10.1038/s41467-021-25610-7 and PMC identifier 8421359.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Na-ion cathode materials operating at high voltage with a stable cycling behavior are needed to develop future high-energy Na-ion cells. However, the irreversible oxygen redox reaction at the high-voltage region in sodium layered cathode materials generates structural instability and poor capacity retention upon cycling. Here, we report a doping strategy by incorporating light-weight boron into the cathode active material lattice to decrease the irreversible oxygen oxidation at high voltages (i.e., >4.0 V vs. Na<sup>+</sup>/Na). The presence of covalent B-O bonds and the negative charges of the oxygen atoms ensures a robust ligand framework for the NaLi<sub>1/9</sub>Ni<sub>2/9</sub>Fe<sub>2/9</sub>Mn<sub>4/9</sub>O<sub>2</sub> cathode material while mitigating the excessive oxidation of oxygen for charge compensation and avoiding irreversible structural changes during cell operation. The B-doped cathode material promotes reversible transition metal redox reaction enabling a room-temperature capacity of 160.5 mAh g<sup>-1</sup> at 25 mA g<sup>-1</sup> and capacity retention of 82.8% after 200 cycles at 250 mA g<sup>-1</sup>. A 71.28 mAh single-coated lab-scale Na-ion pouch cell comprising a pre-sodiated hard carbon-based anode and B-doped cathode material is also reported as proof of concept.