Amorphous Dual‐Layer Coating: Enabling High Li‐Ion Conductivity of Non‐Sintered Garnet‐Type Solid Electrolyte

Abstract

Garnet‐type oxide Li6.4La3Zr1.4Ta0.6O12 (LLZTO) has attracted considerable attention as a highly promising solid state electrolyte. However, its high ionic conductivity is achievable only after high temperature sintering (≈1200 °C) to form dense pellets but with detrimental brittleness and poor contact with electrodes. Herein, a novel strategy to achieve high Li+ ion conductivity of LLZTO without sintering is demonstrated. This is realized by ball milling LLZTO together with LiBH4, which results in a LLZTO composite with unique amorphous dual coating: LiBO2 as the inner layer and LiBH4 as the outer layer. After cold pressing the LLZTO composite powders under 300 MPa to form electrolyte pellets, a high Li+ ion conductivity of 8.02 × 10–5 S cm–1 is obtained at 30 °C, which is four orders of magnitude higher than that of the non‐sintered pristine LLZTO pellets (4.17 × 10–9 S cm–1). The composite electrolyte displays an ultrahigh Li+ transference number of 0.9999 and enables symmetric Li–Li cells to be cycled for 1000 h at 60 °C and 300 h at 30 °C. The significant improvements are attributed to the continuous ionic conductive network among LLZTO particles facilitated by LiBH4 that is chemically compatible and electrochemically stable with Li metal electrode.

The multicomponent synergistic effect of a hierarchical Li0.485La0.505TiO3 solid-state electrolyte for dendrite-free lithium-metal batteries

“…The higher room temperature conductivity and the lower activation energies of BP@LPFL indicate a lowered ion barrier in the solid material and show great application potential at low temperatures. 34,35 The lithium transference number (t Li +) of different solid electrolytes was determined by using the follow equation: 36…”

Preparing Two‐Dimensional Ordered Li0.33La0.557TiO3 Crystal in Interlayer Channel of Thin Laminar Inorganic Solid‐State Electrolyte towards Ultrafast Li+ Transfer

“…XRD patterns in Figure S25 show that, the characteristic peaks of Vr-LLTO LISE display no obvious change after 150 cycles. Meanwhile,the 29 Si and 7 Li NMR spectra in Figure S26 show that, after 150 cycles,t he characteristic peaks at À123.1 ppm corresponding to Si 4+ in Vr and 0.8 ppm corresponding to Li + in LLTO crystal exhibit no obvious change in intensity and position. These jointly prove the chemical stability of Vr-LLTO LISE.…”

“…[6] Gao et al coated LLZTO grains with LiBH 4 and then cold-pressed them into ISE, and reported that the coating layer improved the contact among different grains. [7] Despite these advances,s eldom attempt has been carried out for reducing the intrinsic structural defects of LLTO crystal, which is the root of grain boundary resistance.I na ddition, ISEs are relatively thick (> 200 mm) to maintain their integrated structure.While large thickness leads to decreased energy density for ASSLB and restricts their practical application.…”

Hydrogen bonding enhanced SiO2/PEO composite electrolytes for solid-state lithium batteries

“…The demand for advanced energy storage systems has increased dramatically over the past few decades due to the development of portable electronic devices and the electric vehicle industry. 1–3 Lithium-ion batteries (LIBs) have been widely studied because of their superior performance to other energy storage devices. 4,5 However, there are many problems in commercial LIBs containing liquid electrolytes, such as difficulty in further improving their energy density and poor safety.…”