@article{Wang2023, 
author = {Jie Wang and Lin Wang and Congyan Liu and Yan Wang and Fei Ye and Wen Yan and Bo Liu},
title = {Polyoxovanadate ionic crystals with open tunnels stabilized by macrocations for lithium-ion storage},
year = {2023},
journal = {Nano Research},
volume = {16},
number = {7},
pages = {9267-9272},
keywords = {polyoxometalates (POMs), ionic crystals, lithium-ion battery (LIB), macrocation, energy storage mechanism},
url = {https://www.sciopen.com/article/10.1007/s12274-023-5491-7},
doi = {10.1007/s12274-023-5491-7},
abstract = {Polyoxometalates (POMs) with multiple redox active sites have been reported as charge sponge for lithium-ion batteries (LIBs). Herein, we for the first time introduce a polyoxovanadate (POV) ionic crystals with macrocations, [Ni(Phen)3][ClV14O34]Cl (NiV14, Phen = 1,10-phenanthroline), as an anode material for LIBs. The existence of macrocation [Ni(Phen)3]2+ stabilizes the open tunnels inside NiV14. The NiV14 electrode exhibits superior rate capabilities (1083 mAh·g−1 at 100 mA·g−1 and 384 mAh·g−1 at 2000 mA·g−1) due to the rapid capacitive dominated contribution and high Li+ ions diffusion coefficients (3.3 × 10−12 cm−2·s−1), and it delivers a remarkable cycling stability with a Coulombic efficiency of 99.7% after 1000 cycles at 2000 mA·g−1. Such performance can be attributed to the stable structure of NiV14 and the highly reversible valence changes of vanadium during the charge/discharge processes, which are revealed by a combination of in situ X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and X-ray absorption fine structure (XAFS) measurements. This work not only demonstrates that NiV14 with open tunnels stabilized by macrocation is a promising anode material for high performance LIBs, but also provides important references for the rational design of POMs electrode materials in advanced energy storage systems.}
}