3 years ago

Lithium-Excess Cation-Disordered Rocksalt-Type Oxide with Nanoscale Phase Segregation: Li1.25Nb0.25V0.5O2

Lithium-Excess Cation-Disordered Rocksalt-Type Oxide with Nanoscale Phase Segregation: Li1.25Nb0.25V0.5O2
Mizuki Nakajima, Naoaki Yabuuchi
A Li-excess cation-disordered rocksalt oxide, Li1.25Nb0.25V0.5O2, is proposed as a new high-capacity positive electrode material for rechargeable lithium batteries. Li1.25Nb0.25V0.5O2 delivers a reversible capacity of over 240 mAh g–1 with excellent capacity retention on the basis of the two-electron redox of V3+/V5+ as evidenced by X-ray absorption spectroscopy. Moreover, a small volume change is noted on electrochemical cycles, presumably associated with reversible vanadium migration from octahedral to tetrahedral sites. Additionally, a heat-treated sample shows unexpectedly good rate capability as electrode materials. Observation by scanning transmission electron microscopy reveals that the sample consists of vanadium-rich and niobium-rich nanoparticles formed by phase segregation, which hinders the kinetics as electrode materials. The heat-treatment process effectively changes the cation distribution in the particles and relieves strain induced by ball milling, leading to good rate capability. These findings open a path to design high-capacity electrode materials with the multielectron redox reaction.

Publisher URL: http://dx.doi.org/10.1021/acs.chemmater.7b02343

DOI: 10.1021/acs.chemmater.7b02343

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.