Marchini Florencia, Saha Sujoy, Alves Dalla Corte Daniel, Tarascon Jean Marie
Collège de France, Chaire de Chimie du Solide et de l'Energie, UMR 8260, 11 Place Marcelin Berthelot, 75231 CEDEX 05 Paris, France.
Rèseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459, 33 Rue Saint Leu, 80039 Amiens, France.
ACS Appl Mater Interfaces. 2020 Apr 1;12(13):15145-15154. doi: 10.1021/acsami.9b22937. Epub 2020 Mar 23.
Great hopes are placed on all-solid-state Li-metal batteries (ASSBs) to boost the energy density of the current Li-ion technology. However, these devices still present a number of unresolved issues that keep them far from commercialization; such as interfacial instability, lithium dendrite formation, and lack of mechanical integrity during cycling. To mitigate these limiting aspects, the most advanced ASSB systems presently combine a sulfide- or oxide-based solid electrolyte (SE) with a coated Li-based oxide as the positive electrode and a lithium anode. Through this work, we propose a different twist by switching from layered oxides to layered sulfides as active cathode materials. Herein, we present the performance of a Li-rich layered sulfide of formula LiTiFeS (LTFS) in room temperature operating all-solid-state batteries, using β-LiPS as SE and both InLi and Li anode materials. These batteries exhibit good cyclability, small polarization and, in the case of the Li anode, no initial irreversible capacity. We also suggest the possibility of using this Li-rich sulfide mixed with oxide cathode materials as part of the positive electrode in ASSBs in order to improve the cathode/sulfide SE interface. Our proof of concept using LiNi MnCoO (NMC 622) showed that the addition of a small amount of LTFS had a direct positive impact in the battery performance.
全固态锂金属电池（ASSB）被寄予厚望，有望提高当前锂离子技术的能量密度。然而，这些电池仍存在一些未解决的问题，使其远未实现商业化；例如界面不稳定性、锂枝晶形成以及循环过程中缺乏机械完整性。为了缓解这些限制因素，目前最先进的ASSB系统将硫化物或氧化物基固体电解质（SE）与涂覆的锂基氧化物作为正极和锂负极相结合。通过这项工作，我们提出了一种不同的思路，即将活性阴极材料从层状氧化物转换为层状硫化物。在此，我们展示了分子式为LiTiFeS（LTFS）的富锂层状硫化物在室温运行的全固态电池中的性能，使用β-LiPS作为SE以及InLi和Li负极材料。这些电池表现出良好的循环性能、小极化，并且对于锂负极而言，没有初始不可逆容量。我们还提出了将这种富锂硫化物与氧化物阴极材料混合用作ASSB正极一部分的可能性，以改善阴极/硫化物SE界面。我们使用LiNiMnCoO（NMC 622）的概念验证表明，添加少量LTFS对电池性能有直接的积极影响。
