Design of surface protective layer of LiF/FeF3 nanoparticles in Li-rich cathode for high-capacity Li-ion batteries

Abstract

Advanced lithium-ion batteries for renewable energy storage applications have become a major research interest in recent years. Much better performance can be realized by improvements in the material surface design, especially for the cathode materials. Here, we present a new design for a surface protective layer formed via a facile aqueous solution process in which a nanoarchitectured layer of LiF/FeF 3 is epitaxially grown on bulk hierarchical Li-rich cathode Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2. Coin cell tests of this material in the voltage range of 2-4.8 V indicated a high reversible capacity (260.1 mAh g-1 at 0.1C), superior rate performance (129.9 mAh g-1 at 20C), and excellent capacity retention. Differential scanning calorimetry showed good thermal stability. The enhanced capacity and cycling stability are attributed to the suppression of interfacial side reactions as well as the conversion reaction resulting from the introduction of LiF/FeF 3 as a surface protective layer.

High-energy cathode materials for Li-ion batteries: A review of recent developments

“…Coating the materials with C [122], Al [123], Al 2 O 3 [124], MgO [125], ZnO [126], Li 2 ZrO 3 [127], phosphates [128,129], fluorides [130,131] has been proved to be effective to enhance cycle performance and rate capability. He et al [124] coated 3 wt% Al 2 O 3 on Li[Li 0.2 Co 0.…”

Influences of FeF3 coating layer on the electrochemical properties of Li[Li0.2Mn0.54Ni0.13Co0.13]O2 cathode materials for lithium-ion batteries

“…Recently, a newly design route has been proposed, that is, the combination of an electrochemical conversion reaction cathode and extraction/insertion cathode [21]. The coating materials applied in the route, such as MoO 3 [22], FePO 4 [23], can also react with Li + ions and deliver an additional capacity during the charge-discharge process of active material, simultaneously.…”

“…Compared with the aforementioned coating materials, Iron trifluoride (FeF 3 ), as an alternative cathode material, has high theoretical capacities of 237 mAh g − 1 at 2.0-4.5 V through the intercalation reaction of one lithium ion (Fe 3+ F 3 + 1Li + + 1e − → LiFe 2+ F 3 ) [24]. Moreover, its finally reaction products, LiF and Fe nanodomains (FeF 3 + 3Li + + 3e − → Fe + 3LiF), can also serve as a protective layer to restrain the electrolyte decomposition on the cathode surface and enhance the cycle stability [21]. Thus, FeF 3 will be an attractive material as modified additives or surface coating.…”

Improve First-Cycle Efficiency and Rate Performance of Layered-Layered Li1.2Mn0.6Ni0.2O2Using Oxygen Stabilizing Dopant

“…4,13,[19][20][21][22][23] In spite of the improvement in the electrochemical performance owing to the contribution of LiMO 2 , the rate performance and the first-cycle efficiency of LLO still cannot meet the requirements for practical application. [24][25][26][27][28][29][30] Further breakthrough of the LLO requires the direct suppressing of the O 2 releasing from the Li 2 MnO 3 . [8][9]19 In this work, barium ion was investigated as an oxygen stabilizing dopant to improve both the rate performance and the first-cycle efficiency of the Li-rich layered-layered Li 1.2 Mn 0.6 Ni 0.2 O 2 .…”