Ze Feng,Shan Zhang,Xiaobing Huang,Yurong Ren,Dan Sun,Yougen Tang,Qunxuan Yan,Haiyan Wang
Nickel-rich cathode materials, owing to their high energy density and low cost, are considered to be one of the cathodes with the most potential in next-generation lithium-ion batteries. Unfortunately, this kind of cathode with highly active surface is easy to react with H 2 O and CO 2 when exposed to ambient air, resulting in the formation of lithium impurities and interfacial phase transition as well as deterioration of the electrochemical properties. In this work, the evolution mechanism of the structure and interface of LiNi 0.8 Co 0.1 Mn 0.1 O 2 during air-exposure is systematically investigated. Furthermore, a facile reviving strategy is proposed to restore the degraded LiNi 0.8 Co 0.1 Mn 0.1 O 2 by using LiPO 3 as the repair agent. The lithium impurities on the surface of the degraded sample can transform into the repair/coating layer, and part of the rock salt phase on the subsurface can revive to layered phase after repair heat treatment. As a result, the optimized cathode delivers an initial discharge capacity of 198.3 mAh g −1 at 0.1C and a capacity retention of 85.5% after 50 cycles. Although slightly lower than the bare sample (201 mAh g −1 and 88%), they are obviously higher than the exposed samples (166.5 mAh g −1 and 40.4%). The regenerated electrochemical properties should be attributed to the multifunctional repair layer that can efficiently reduce the surface lithium impurities, prevent the corrosion of electrolyte, and improve the interfacial Li + diffusion kinetics. This work can effectively reduce the waste of the degraded Ni-rich ternary materials and realize the transformation of “waste” into wealth.
In lithium batteries, the interface between electrolytes and electrodes with optimized structural stability and fast charge transfer kinetics plays a pivotal role in achieving overall cycle and rate performance. Introducing a uniform interfacial layer that conducts Li + ions while insulating electrons, through atomic layer deposition (ALD) of lithium compounds, has shown promise in facilitating lithium ion transport and enhancing interface stability. However, synthesizing lithium compounds with both robust chemical stability and a broad electrochemical window using ALD poses challenges due to the difficulty of obtaining desired products under specific ALD reaction conditions. In this study, this challenge by investigating Li 3 PO 4 is addressed, a compound grown by ALD that exhibits a noteworthy property: the in situ formation of a more stable LiPO 3 phase under high applied voltage. The LiPO 3 phase possesses an extended theoretical stability window (LiPO 3 : 2.48-5.00 V versus Li 3 PO 4 : 0.69-4.21 V), and its emergence substantially enhances the electrochemical performance of all-solid-state lithium batteries based on polyethylene oxide (PEO). This work not only presents experimental evidence of the in situ transformation of the interfacial layer but also offers a pragmatic approach to realizing all-solid-state lithium batteries with elevated energy density, emphasizing safety and stability considerations.
危险品化学品经营许可证（带存储）