Regulating Incompatible Interfaces and Electron/Ion Transport in Lithium Metal Solid State Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Batteries

Background:

• Large interfacial impedance and poor ion transport hinder LATP-based solid-state battery development.
• Spontaneous reactions at the LATP/Li metal interface impede battery performance and safety.

Purpose of the Study:

• To construct a fast Li+ transfer and electron-blocking interface on LATP.
• To enhance the interfacial contact between LATP and Li metal.
• To improve the electrochemical performance and stability of LATP-based solid-state batteries.

Main Methods:

• In situ electrochemical reaction of In2O3 with Li metal to form a Li2O/LixIn interface on LATP.
• Fabrication of Li/In2O3@LATP/Li symmetric batteries.
• Testing of Li/In2O3@LATP/LiFePO4 and Li/In2O3@LATP/Li1.2Mn0.6Ni0.2O2 full batteries.

Main Results:

• Reduced initial resistance from 1211.4 to 106.5 Ω cm-2.
• Increased critical current density to 1.9 mA cm-2.
• Stable cycling over 3700 h without dendrites at 0.2 mA cm-2/0.2 mAh cm-2.
• Full battery with LiFePO4 cathode showed a decay rate of ≈0.015% per cycle after 600 cycles.
• High voltage compatibility (4.8 V) with a nickel-manganese-cobalt cathode.

Conclusions:

• The Li2O/LixIn interface effectively addresses interfacial issues in LATP solid-state batteries.
• This interface promotes fast Li+ transport and suppresses Li dendrite growth.
• The developed solid-state batteries exhibit excellent stability, high performance, and potential for practical applications.