Quantitative predictions of the Li intercalation voltage and of the electronic properties of rechargeable battery cathode materials are a substantial challenge for first-principles theory due to the possibility of (1) strong correlations associated with localized transition metal $d$ electrons and (2) significant van der Waals (vdW) interactions in layered systems, both of which are not accurately captured by standard approximations to density functional theory (DFT). Here, we perform a systematic benchmark of electronic structure methods based on the widely used generalized-gradient approximation of Perdew, Burke, and Ernzerhof (PBE) and the new strongly constrained and appropriately normed (SCAN) meta-generalized-gradient approximation for battery cathode materials. Studying layered ${\mathrm{Li}}_x{\mathrm{TiS}}_2, {\mathrm{Li}}_x{\mathrm{NiO}}_2$, and ${\mathrm{Li}}_x{\mathrm{CoO}}_2$, olivine ${\mathrm{Li}}_x{\mathrm{FePO}}_4$, and spinel ${\mathrm{Li}}_x{\mathrm{Mn}}_2{\mathrm{O}}_4$, we compute the voltage, crystal structure, and electronic structure with and without extensions to incorporate onsite Hubbard interactions and vdW interactions. Within pure DFT (i.e., without corrections for onsite Hubbard interactions), SCAN is a significant improvement over PBE for describing cathode materials, decreasing the mean absolute voltage error by more than 50%. Although explicit vdW interactions are not critical and in cases even detrimental when applied in conjunction with SCAN, Hubbard-$U$ corrections are still in general necessary to achieve reasonable agreement with experiment. We show that no single method considered here can accurately describe the voltage and overall structural, electronic, and magnetic properties (i.e., errors no more than 5% for voltage, volume, band gap, and magnetic moments) of battery cathode materials, motivating a strong need for improved electronic structure approaches for such systems.

中文翻译：

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可充电电池正极材料中锂离子嵌入电压的预测：交换相关函数，范德华相互作用和哈伯德U的影响

Li插层电压和可再充电电池阴极材料的电子性能的定量预测对于第一原理理论是一个重大挑战，因为可能（1）与局部过渡金属有很强的相关性 $d$电子和（2）分层系统中的显着范德华（vdW）相互作用，这两者都无法通过密度泛函理论（DFT）的标准近似准确地捕获。在这里，我们基于广泛使用的Perdew，Burke和Ernzerhof（PBE）的广义梯度逼近以及电池阴极的新的强约束和适当归一化（SCAN）亚广义梯度逼近，对电子结构方法进行了系统的基准测试材料。学习分层${里}_X{钛}_2， {里}_X{\mathrm{氧化镍}}_2$和 ${里}_X{\mathrm{首席运营官}}_2$，橄榄石 ${里}_X{\mathrm{磷酸铁}}_4$和尖晶石 ${里}_X{锰}_2{\mathrm{Ø}}_4$，我们将计算具有扩展和不扩展的电压，晶体结构和电子结构，以结合现场Hubbard交互作用和vdW交互作用。在纯DFT中（即，无需对现场Hubbard相互作用进行校正），SCAN在描述阴极材料方面比PBE显着改进，将平均绝对电压误差降低了50％以上。尽管显式的vdW互动并不重要，并且在与SCAN结合使用时甚至有害，但Hubbard-$ü$通常仍需要进行更正以与实验取得合理的一致性。我们表明，这里考虑的任何一种方法都无法准确地描述电池阴极材料的电压以及整体结构，电子和磁性能（即，电压，体积，带隙和磁矩的误差不超过5％），从而激发了强烈需要用于此类系统的改进的电子结构方法。