Electrolyte/Electrode Interfaces in All-Solid-State Lithium Batteries: A Review

Abstract

All-solid-state lithium batteries are promising next-generation energy storage devices that have gained increasing attention in the past decades due to their huge potential towards higher energy density and safety. As a key component, solid electrolytes have also attracted significant attention and have experienced major breakthroughs, especially in terms of Li-ion conductivity. However, the poor electrode compatibility of solid electrolytes can lead to the degradation of electrolyte/electrode interfaces, which is the major cause for failure in all-solid-state lithium batteries. To address this, this review will summarize the indepth understanding of physical and chemical interactions between electrolytes and electrodes with a focus on the contact, charge transfer and Li dendrite formation occurring at electrolyte/electrode interfaces. Based on mechanistic analyses, this review will also briefly present corresponding strategies to enhance electrolyte/electrode interfaces through compositional modifications and structural designs. Overall, the comprehensive insights into electrolyte/electrode interfaces provided by this review can guide the future investigation of all-solid-state lithium batteries.

Uniform and Anisotropic Solid Electrolyte Membrane Enables Superior Solid‐State Li Metal Batteries

“…Inorganic electrolytes usually exhibit attractive Li-ion conductivities, high mechanical moduli, and wide electrochemical stability windows, but their rigidness and brittleness seriously decrease the electrode compatibility. [12,13] Polymer electrolytes are more flexible and viscoelastic, which can easily form well-contacted electrolyte/electrode interfaces, but they suffer from low Li-ion conductivity, poor mechanical strength, and bad electrochemical stability. [14,15] The strategy of forming composite solid electrolytes (CSE) by incorporating inorganic electrolytes into polymer electrolyte matrix is very promising that can not only improve ionic conductivity, but also enhance the mechanical strength without sacrificing flexibility.…”

“…Inorganic electrolytes usually exhibit attractive Li‐ion conductivities, high mechanical moduli, and wide electrochemical stability windows, but their rigidness and brittleness seriously decrease the electrode compatibility. [ 12,13 ] Polymer electrolytes are more flexible and viscoelastic, which can easily form well‐contacted electrolyte/electrode interfaces, but they suffer from low Li‐ion conductivity, poor mechanical strength, and bad electrochemical stability. [ 14,15 ]…”

Nominally stoichiometric Na3(WxSixSb1−2x)S4 as a superionic solid electrolyte

“…1 The use of inorganic solid-electrolytes (ISEs) in ASSBs is expected to substantially improve operational safety by alleviating the problems of flammability and high-temperature thermal runaway. 2,3 The high mechanical strength of ISEs also enables the use of lithium metal as an anode of choice, which would lessen the concern of dendrites, 4 thereby contributing to higher energy densities on the cell level. From the aspect of battery design, the use of ISEs could render the bipolar stacking of multiple cells to be straightforward, which would also contribute to a higher level of energy density in ASSBs.…”

Modulating composite polymer electrolyte by lithium closo-borohydride achieves highly stable solid-state battery at 25°C

“…Solid-state lithium batteries (SSLBs) have attracted considerable attention owing to their potential to mitigate safety issues associated with organic liquid electrolytes, such as leakage, flammability, and short circuiting (via dendritic growth) of the batteries [1][2][3][4]. Solid electrolytes play a crucial role in the overall electrochemical performance of SSLBs.…”