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      https://www.ias.ac.in/article/fulltext/boms/036/07/1331-1337

    • Keywords

       

      Lithium ion battery; cathodes; density functional theory; density of states; Bader charge analysis; electrochemical potential.

    • Abstract

       

      First-principles prediction of enhancement in the electrochemical potential of LiCoO2 with aluminum substitution has been realized through earlier experiments. For safer and less expensive Li-ion batteries, it is desirable to have a similar enhancement for alternative cathode materials, LiFePO4 and LiCoPO4. Here, we present first-principles density functional theory based analysis of the effects of aluminum substitution on electrochemical potential of LiCoO2, LiFePO4 and LiCoPO4. While Al substitution for transition metal results in increase in electrochemical potential of LiCoO2, it leads to reduction in LiFePO4 and LiCoPO4. Through comparative topological analysis of charge density of these materials, we identify a ratio of Bader charges that correlates with electrochemical potential and determine the chemical origin of these contrasting effects: while electronic charge from lithium is transferred largely to oxygen in LiCoO2, it gets shared by the oxygen and Co/Fe in olivine phosphates due to strong covalency between O and Co/Fe. Our work shows that covalency of transition metal–oxygen bond plays a key role in determining battery potential.

    • Author Affiliations

       

      Arun Kumar Varanasi1 Phani Kanth Sanagavarapu1 Arghya Bhowmik1 Mridula Dixit Bharadwaj1 Balasubramanian Narayana1 Umesh V Waghmare2 Dipti Deodhare3 Alind Sharma3

      1. Centre for Study of Science, Technology and Policy, Dr Raja Ramanna complex, Bangalore 560 001, India
      2. Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
      3. Centre for Artificial Intelligence and Robotics, DRDO Complex, C.V. Raman Nagar, Bangalore 560 093, India
    • Dates

       
  • Bulletin of Materials Science | News

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