Ultrathin 3 V Spinel Clothed Layered <scp>Lithium‐Rich</scp> Oxides as Heterostructured Cathode for <scp>High‐Energy</scp> and <scp>High‐Power</scp> Li‐ion Batteries<sup>†</sup>
Liqin Dai, Ning Li, Lai Chen, Yuefeng Su, Cheng‐Meng Chen, Fangyuan Su, Liying Bao, Shi Chen, Feng Wu
Abstract
Main observation and conclusion In an attempt to overcome the drawbacks of high‐capacity layered lithium‐rich cathodes x Li 2 MnO 3 ·(1– x ) LiMO 2 (0 < x < 1, M = Mn, Ni, and Co), the spinel clothed layered heterostructured materials, x ’Li 4 Mn 5 O 12 ·(1– x ’) Li[Li 0.2 Mn 0.55 Ni 0.15 Co 0.1 ]O 2 ( x ’ = 0.01, 0.03, 0.05) have been proposed and synthesized as high‐performance cathode materials for high‐energy and high‐power Li‐ion batteries. Based on the characterizations of X‐ray diffraction (XRD), transmission electron microscopy (TEM), Raman scattering spectroscopy, it is indicated that ultrathin 3 V spinel Li 4 Mn 5 O 12 has been successfully clothed on the layered lithium‐rich cathode. Electrochemical tests demonstrate the sample 0.01Li 4 Mn 5 O 12 ·0.99 Li[Li 0.2 Mn 0.55 Ni 0.15 Co 0.1 ]O 2 with an ultrathin clothing layer of spinel phase, exhibits the highest reversible capacity of 289.4 mAh g –1 and maintains 259.8 mAh g –1 after 80 cycles at 0.1 C rate. Meanwhile, it delivers outstanding rate discharge capacities of 229.4 mAh g –1 at 1 C, 216.8 mAh g –1 at 2 C and 184.4 mAh g –1 at 5 C as well as alleviated voltage fade. It is believed the ultrathin clothing spinel layer plays a vital role in the modification of the materials kinetics, and structural and electrochemical stability of the heterostructured cathode.