论文标题
障碍和掺杂对电子结构的影响和李$ _ {3} $ v $ _ {2} $ o $ $ $ _ {5} $的电子结构和扩散属性的影响
Effect of disorder and doping on electronic structure and diffusion properties of Li$_{3}$V$_{2}$O$_{5}$
论文作者
论文摘要
V $ _ {2} $ o $ $ _ {5} $在其$ω$ phope（li $ _ {3} $ v $ _ {2} $ _ {2} $ o $ $ _ {5} $）具有多余的锂是在低温和快速充电条件下的石墨阳极的潜在替代方案，因此由于其低温和快速的充电条件（0.6 li $^{+} $/li（s））和高锂运输速率。如大多数有序的材料中所观察到的那样，operando阳离子障碍可以在电荷补偿机制，阴离子活性，锂扩散和操作电压中产生重大变化。在这项工作中，我们报告了结构失真，电子结构和迁移屏障的差异，并使用第一原理计算伴随着无序。由于锂原子在无序状态下的隔离，我们观察到更大的失真，金属行为的出现以及来自费米水平附近的非构氧状态的潜在阴离子活性。氧化还原能力可以通过掺杂3D金属来调整，该金属可以调整参与的阳离子状态，以及可以稳定或抑制阴离子状态的氟取代。此外，发现对阴离子活性的抑制可减少结构变形，对于缓解电压褪色和磁滞至关重要。在存在障碍的情况下，扩散屏障计算表明其余的3D paths lithium跳的激活在有序构型中不可用，这解释了其在实验中观察到的快速充电能力。
V$_{2}$O$_{5}$ in its $ω$ phase (Li$_{3}$V$_{2}$O$_{5}$) with excess lithium is a potential alternative to the graphite anode for lithium-ion batteries at low temperature and fast charging conditions due to its safer voltage (0.6 V vs Li$^{+}$/Li(s)) and high lithium transport rate. In-operando cationic disorder, as observed in most ordered materials, can produce significant changes in charge compensation mechanisms, anionic activity, lithium diffusion and operational voltages. In this work, we report the variation in structural distortion, electronic structure and migration barrier accompanied by disorder using first-principles calculations. Due to segregation of lithium atoms in the disordered state, we observe greater distortion, emergence of metallic behaviour and potential anionic activity from non-bonding oxygen states near the Fermi level. Redox capacity can be tuned by doping with 3d metals which can adjust the participating cationic states, and by fluorine substitution which can stabilize or suppress anionic states. Moreover, suppression of anionic activity is found to decrease structural distortion, crucial for mitigating voltage fade and hysteresis. Diffusion barrier calculations in the presence of disorder indicate the activation of the remaining 3D-paths for lithium hopping which are unavailable in the ordered configuration, explaining its fast-charging ability observed in experiments.
