UC Berkeley

Adv. Funct. Mater. 2019, 29, 1902392 In the initially published version of this article, the authors inadvertently omitted mention and citations to related work. The following text is included as part of the Introduction: In this work, we investigated and contrasted alkali ion (Li, Na, and K) intercalation properties in KxVPO4F (x ∼ 0) by a combined experimental and computational study. Related work has been done by Fedotov et al. and Nikitina et al. Fedotov et al. demonstrated that depotassiated KxVPO4F (x ∼ 0.15) can intercalate Li ions reversibly, and found that Li ions occupy under-coordinated sites, compared to K sites. Later, alkali ion diffusivity in KxVPO4F (x ∼ 0.5) and RbxVPO4F (x ∼ 0.5) was investigated and compared by Nikitina et al. and Fedotov et al., respectively. These authors found that K migration along the c-axis has a low barrier (≈200 meV) and the Li ion diffusivity is lower than for Na and K ions in the KxVPO4F (x ∼ 0.5) structure despite its smaller ionic size. There are some differences between the Fedotov et al.'s compound and ours in the voltage profile, which is attributable to different V-oxidation and O/F between the two as previously discussed. In addition, we removed all the K from KxVPO4F in our work in order not to have interaction between the inserted alkali (Li and Na) and the remaining K. The authors apologize for any inconvenience or misunderstanding that this error may have caused.