Analysis of an all-solid state nanobattery using molecular dynamics simulations under an external electric field

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Current lithium-ion battery (LIB) technology needs significant improvements in performance, capacity, charging speed, and cost for widespread adoption in e-mobility and grid storage.
• Lithium-metal anodes offer a ten-fold increase in specific capacity over graphite but suffer from high reactivity with conventional liquid electrolytes.
• Solid-state electrolytes (SSEs) are being explored as a safer alternative to liquid electrolytes for advanced battery designs, particularly those utilizing lithium-metal anodes.

Purpose of the Study:

• To theoretically analyze the charging process within a full nanobattery system incorporating a lithium-metal anode and a solid-state electrolyte.
• To investigate the behavior of the solid electrolyte interphase (SEI) and SSE during battery charging, focusing on ion transport and thermal profiles.
• To evaluate the potential of this nanobattery configuration for next-generation energy storage applications.

Main Methods:

• A theoretical analysis was performed on a nanobattery model comprising a LiCoO2 cathode, Li7P2S8I SSE, Li-metal anode, and a Li3P/Li2S SEI layer.
• Simulations were conducted by applying an external electric field to model the battery charging process.
• Key parameters such as temperature profiles and lithium-ion transport through the SSE and SEI were estimated and analyzed.

Main Results:

• A slight temperature increase was observed at the SEI layer due to interfacial reactions, with temperature profiles influenced by the charging current and applied electric field.
• The nanobattery exhibited an open-circuit voltage (OCV) of 3.86 V without an external field, comparable to commercial cobalt-based LIBs.
• Detailed analysis of lithium-ion transport pathways through the SSE and SEI layers during charging was provided.

Conclusions:

• The study provides valuable insights into the electrochemical and thermal behavior of solid-state nanobatteries with lithium-metal anodes.
• Understanding Li-ion transport across the SEI and SSE is critical for optimizing charging dynamics and overall battery performance.
• The findings contribute to the development of advanced solid-state batteries for demanding applications like electric vehicles and grid-scale energy storage.