Design of a trigonal halide superionic conductor by regulating cation order-disorder.

Lithium-metal-halides have emerged as a class of solid electrolytes that can deliver superionic conductivity comparable to that of state-of-the-art sulfide electrolytes, as well as electrochemical stability that is suitable for high-voltage (>4 volt) operations. We show that the superionic conduction in a trigonal halide, such as LiMCl [where metal (M) is Y or Er], is governed by the in-plane lithium percolation paths and stacking interlayer distance. These two factors are inversely correlated with each other by the partial occupancy of M, serving as both a diffusion inhibitor and pillar for maintaining interlayer distance.

Coupling structural evolution and oxygen-redox electrochemistry in layered transition metal oxides.

Lattice oxygen redox offers an unexplored way to access superior electrochemical properties of transition metal oxides (TMOs) for rechargeable batteries. However, the reaction is often accompanied by unfavourable structural transformations and persistent electrochemical degradation, thereby precluding the practical application of this strategy. Here we explore the close interplay between the local structural change and oxygen electrochemistry during short- and long-term battery operation for layered TMOs.

Challenges and Strategies towards Practically Feasible Solid-State Lithium Metal Batteries.

Remarkable improvement of the ionic conductivity of inorganic solid electrolytes (SEs) exceeding 10 mS cm at room temperature has opened up the opportunities to realize the commercialization of solid-state batteries (SSBs). The transition to the intrinsically inflammable SEs also promises that SSBs would successfully utilize lithium metal anode thus achieving the high-energy-density lithium metal batteries without the risk of a safety hazard. However, the practical operation of solid-state lithium metal batteries (SSLMBs) still faces the challenges of the poor cycle stability and the low energy efficiency, which are coupled with the interface stability and even with the dendrite growth of lithium metal.

Aqueous ionic effect on electrochemical breakdown of Si-dielectric-electrolyte interface.

The breakdown of thin dielectric films (SiO, SiN, HfO) immersed in aqueous electrolyte was investigated. The current and the kinetics of dielectric breakdown caused by large cathodic electric field applied across the dielectric layer reveal the electrochemical nature of dielectric materials. Electrolytes play a huge role in the established dielectric-electrolyte interface with respect to the overall electrical behavior of the system.

Planting Repulsion Centers for Faster Ionic Diffusion in Superionic Conductors.

The successful launch of solid-state batteries relies on the discovery of solid electrolytes with remarkably high ionic conductivity. Extensive efforts have identified several important superionic conductors (SICs) and broadened our understanding of their superionic conductivity. Herein, we propose a new design strategy to facilitate ionic conduction in SICs by planting immobile repulsion centers.

Synergistic multi-doping effects on the Li7La3Zr2O12 solid electrolyte for fast lithium ion conduction.

Here, we investigate the doping effects on the lithium ion transport behavior in garnet Li7La3Zr2O12 (LLZO) from the combined experimental and theoretical approach. The concentration of Li ion vacancy generated by the inclusion of aliovalent dopants such as Al(3+) plays a key role in stabilizing the cubic LLZO. However, it is found that the site preference of Al in 24d position hinders the three dimensionally connected Li ion movement when heavily doped according to the structural refinement and the DFT calculations.