Multilayered, Bipolar, All-Solid-State Battery Enabled by a Perovskite-Based Biphasic Solid Electrolyte

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Solid electrolytes offer a safer alternative to liquid electrolytes in lithium-ion batteries, addressing safety concerns.
• A bipolar design in battery modules increases volumetric energy density and simplifies electrical connections.
• Developing stable and conductive solid electrolytes is crucial for advancing all-solid-state batteries (ASSBs).

Purpose of the Study:

• To design and construct a multilayered, bipolar-type all-solid-state battery (ASSB) using a novel biphasic solid electrolyte (BSE).
• To evaluate the electrochemical performance and stability of the BSE-based ASSB.
• To demonstrate the feasibility of a bipolar ASSB for high-voltage and high-energy applications.

Main Methods:

• Fabrication of a flexible and freestanding biphasic solid electrolyte (BSE) membrane composed of Li$_{0.29}$La$_{0.57}$TiO$_{3}$ perovskite and poly(ethylene oxide) (PEO).
• Assembly and electrochemical testing of single-layered ASSBs using the BSE membrane.
• Construction and testing of a proof-of-concept bipolar ASSB with three unit cells connected in series using BSE membranes and bipolar plates.

Main Results:

• The BSE membrane exhibited high Li$^{+}$ conductivity (1.2×10$^{-4}$ S cm$^{-1}$) and enhanced electrochemical/thermal stability compared to PEO-only electrolytes.
• Single-layered ASSBs showed a high reversible capacity (123 mAh g$^{-1}$) and excellent cycling stability over 100 cycles.
• The bipolar ASSB demonstrated high thermal stability and reversible operation without short circuits or leakage, confirming its potential.

Conclusions:

• Biphasic solid electrolytes (BSEs) are promising for developing safer and high-energy density all-solid-state batteries (ASSBs).
• The bipolar design enabled by BSEs facilitates increased energy density and simplified module construction.
• This work presents a viable approach for fabricating bipolar ASSBs with improved safety and performance characteristics.