Li₂(BH₄)(NH₂) Nanoconfined in SBA-15 as Solid-State Electrolyte for Lithium Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• High-performance all-solid-state batteries require solid electrolytes with superior lithium-ion conductivity and electrochemical stability.
• Current limitations in solid electrolytes hinder the development of safe and efficient energy storage solutions.

Purpose of the Study:

• To develop a novel solid electrolyte by nanoconfining lithium borohydride amide (Li₂(BH₄)(NH₂)) within a mesoporous silica structure (SBA-15).
• To evaluate the electrochemical properties and performance of the nanoconfined electrolyte in all-solid-state batteries.

Main Methods:

• Utilized a melting-infiltration approach to encapsulate Li₂(BH₄)(NH₂) within the pores of SBA-15.
• Characterized the Li-ion conductivity, electrochemical stability window, and Li-ion transference number of the resulting composite electrolyte.
• Assembled and tested all-solid-state battery cells using the developed electrolyte.

Main Results:

• Achieved a high Li-ion conductivity of 5.0 × 10^-3 S cm^-1 at 55 °C.
• Demonstrated an electrochemical stability window of 0 to 3.2 V and a high Li-ion transference number of 0.97.
• The Li|Li₂(BH₄)(NH₂)@SBA-15|TiS₂ cells exhibited stable cycling with a reversible specific capacity of 150 mAh g^-1 and 96% Coulombic efficiency after 55 cycles.

Conclusions:

• Nanoconfinement of Li₂(BH₄)(NH₂) in SBA-15 significantly enhances its performance as a solid electrolyte.
• The developed composite electrolyte shows great promise for enabling stable and efficient operation of all-solid-state lithium batteries.