National and Local United Engineering Laboratory for Power Batteries, Faculty of Chemistry, Northeast Normal University, Changchun, Jilin, 130024, P. R. China.
CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing, 100190, P. R. China.
Adv Mater. 2017 Sep;29(33). doi: 10.1002/adma.201701968. Epub 2017 Jun 22.
Sodium-ion batteries (SIBs) are still confronted with several major challenges, including low energy and power densities, short-term cycle life, and poor low-temperature performance, which severely hinder their practical applications. Here, a high-voltage cathode composed of Na V (PO ) O F nano-tetraprisms (NVPF-NTP) is proposed to enhance the energy density of SIBs. The prepared NVPF-NTP exhibits two high working plateaux at about 4.01 and 3.60 V versus the Na /Na with a specific capacity of 127.8 mA h g . The energy density of NVPF-NTP reaches up to 486 W h kg , which is higher than the majority of other cathode materials previously reported for SIBs. Moreover, due to the low strain (≈2.56% volumetric variation) and superior Na transport kinetics in Na intercalation/extraction processes, as demonstrated by in situ X-ray diffraction, galvanostatic intermittent titration technique, and cyclic voltammetry at varied scan rates, the NVPF-NTP shows long-term cycle life, superior low-temperature performance, and outstanding high-rate capabilities. The comparison of Ragone plots further discloses that NVPF-NTP presents the best power performance among the state-of-the-art cathode materials for SIBs. More importantly, when coupled with an Sb-based anode, the fabricated sodium-ion full-cells also exhibit excellent rate and cycling performances, thus providing a preview of their practical application.
钠离子电池（SIBs）仍然面临着一些重大挑战，包括能量和功率密度低、短期循环寿命短以及低温性能差，这些严重限制了它们的实际应用。在这里，提出了一种由 NaV(PO4)OF 纳米四面体（NVPF-NTP）组成的高压正极，以提高 SIBs 的能量密度。所制备的 NVPF-NTP 在约 4.01 和 3.60 V 相对于 Na/Na 时表现出两个高工作平台，比容量为 127.8 mA h g-1。NVPF-NTP 的能量密度高达 486 Wh kg-1，高于之前报道的大多数用于 SIBs 的正极材料。此外，由于在 Na 嵌入/脱出过程中具有较低的应变（≈2.56%体积变化）和优越的 Na 传输动力学，原位 X 射线衍射、恒电流间歇滴定技术和不同扫描速率下的循环伏安法证明了这一点，NVPF-NTP 表现出长期循环寿命、优异的低温性能和出色的高倍率性能。Ragone 图的比较进一步揭示了 NVPF-NTP 在 SIBs 的最先进正极材料中具有最佳的功率性能。更重要的是，当与基于 Sb 的负极结合时，所制造的钠离子全电池也表现出优异的倍率和循环性能，从而为它们的实际应用提供了预览。
