2016/12/21 by Krishna Rao Ragavendran, Ragavendran, Krishna Rao, Prabhat Mandal +3
Physics and Astronomy · #FOS: Physical sciences #Strongly Correlated Electrons (cond-mat.str-el) #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.1612.07092
6 pages
arxiv created 2016/12/21 · arxiv updated 2016/12/22
Understanding the basic physics related to archetypal lithium battery material (such as LiCoyMn2-yO4) is of considerable interest and is expected to aid designing of cathodes of high capacity. The relation between electrochemical performance, activated-transport parameters, thermal expansion, and cooperativity of electron-phonon-interaction distortions in LiCoyMn2-yO4 is investigated. The first order cooperative-normal-mode transition, detected through coefficient of thermal expansion, is found to disappear at a critical doping (y ∼ 0.16); interestingly, for y \gtrsim 0.16 the resistivity does not change much with doping and the electrochemical capacity becomes constant over repeated cycling. The critical doping y ∼ 0.16 results in breakdown of the network of cooperative/coherent normal-mode distortions; this leads to vanishing of the first-order transition, establishment of hopping channels with lower resistance, and enhancing lithiation and delithiation of the battery, thereby minimizing electrochemical capacity fading.