Microscopic Segregation Dominated Nano‐Interlayer Boosts 4.5 V Cyclability and Rate Performance for Sulfide‐Based All‐Solid‐State Lithium Batteries

Abstract

density and low safety caused by flammable liquid electrolytes, become the bottleneck restraining the future growth of development. With the concerns of higher energy density (>500 Wh kg -1 ) and a lower probability of dangerous events, all-solid-state lithium batteries (ASSLBs) have become the most anticipated nextgeneration energy storage devices. In particular, solid-state batteries installed with high Li + conductive (1-25 mS cm -1 ) sulfide electrolytes (SSEs) become high-profile future for energy storage systems. [1][2][3] Regardless of superior σ Li+ , the output of sulfide-base solid-state batteries is severely limited by unstable electrode/electrolyte interface, causing high interfacial resistance to originate from various factors, e.g., space charge layer (SCL) and contact loss. Interfacial degeneration is the principal culprit of sub-standard performance, low energy density, and pre-mature failure, and hence, restrains the future growth of sulfide-based ASSLBs. [4,5] Furthermore, degradation of the oxide-based cathode, particularly at high charging cut-off voltage (≥4.5 V), has widely been reported and needs to be addressed for high-energy-density (Wh Kg −1 ) ASSLBs.LCO has incontestable advantages, e.g., high theoretical capacity (274 mAh g −1 ), Li + /e − conductivity, theoretical density, To implement the growing requirement for higher energy density all-solid-state lithium batteries (ASSLBs), further increasing the working voltage of LiCoO 2 (LCO) is a key to breaking through the bottleneck. However, LiCoO 2 severe structural degradation and side reactions at the cathode interface obstruct the development of high-voltage sulfide-based ASSLBs (≥4.5 V). Herein, a nanometric Li 1.175 Nb 0.645 Ti 0.4 O 3 (LNTO) coated LCO cathode where microscopic Ti and Nb segregation at the interface during cycling potentially stabilizes the cathode lattice, and minimizes side reactions, simultaneously, is designed. Advanced transmission electron microscopy reveals that the stable spinel phase minimizes the micro stress at the cathode interface, avoids structure fragmentation, and hence significantly enhances the long-term cyclic stability of LNTO@LCO @ 4.5 V. Moreover, the differential phase contrast scanning transmission electron microscopy (DPC-STEM) visualizes the nano-interlayer LNTO to boost Li + migration at the cathode interface. Electrochemical impedance spectroscopy (EIS) reveals that sulfide-based cells with the LNTO nanolayer effectively reduce the interfacial resistance to 140 Ω compared to LiNbO 3 (235 Ω) over 100 cycles. Therefore, 4.5 V sulfide-based ASSLBs offer gratifying long-cycle stability (0.5 C for 1000 cycles, 88.6%), better specific capacity, and rate performance (179.8 mAh g -1 at 0.1 C, 97 mAh g -1 at 2 C).

Toward Ultrastable Metal Anode/Li6PS5Cl Interface via an Interlayer as Li Reservoir

“…According to the analysis details for Figure S12, it is concluded that, in all-solid-state batteries, the Pre In anode has the ability of improving interfacial compatibility and effective utilization of active Li, which is inseparable from the multifunctional interlayer formed on it. In comparison to other reports, ,,,− sulfide-based solid-state cells in this work show superior performances in view of the cycling life span, capacity retention, and areal current density (Figure e), which proves the effectiveness of a generated interlayer on the improvement of metal anode/LPSCl interface stability.…”

TiO2 Nanoparticles Assisted LiNbO3-Coated LiNi0.8Co0.1Mn0.1O2 Cathode for Lithium-Ion Batteries

“…Ti doping LiNbO 3 might be beneficial of Li + transmission as a coating particle. 29 To assess the ionic conductivity of pure LiNbO 3 and TO@ LNO (500, 600, and 700) particles, the respective ionic conductivity values were determined using EIS, as illustrated in Figure S3. The histogram shows that the ionic conductivity of the TO@LNO 700 particles is superior.…”

Surface Engineering Strategy Enables 4.5 V Sulfide-Based All-Solid-State Batteries with High Cathode Loading and Long Cycle Life

“…To solve these tough issues, pioneer researchers generally design various inorganic coating layers on the cathode to inhibit the side reactions between the cathode and sulfide SEs . Typical examples include Li 2 SiO 3 , Li x Zr 2 (PO 4 ) 3 , Li 3– x B 1– x C x O 3 , Li 2 CoTi 3 O 8 , Li 1.175 Nb 0.645 Ti 0.4 O 3 , and LiBa­(B 3 O 5 ) 3 , and all of them successfully enable operation of LCO at 4.5 V. However, none of them can concurrently achieve high discharge capacity, great rate performance, and long cycle stability. We consider that maybe two reasons limit the effectiveness of these inorganic coating layers.…”