In Situ Optical Observation of Lithium Dendrite Pattern in Solid Polymer Electrolytes

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Solid polymer electrolytes (SPEs) are promising for high-performance solid-state lithium metal batteries (SSLMBs).
• Addressing safety and energy density issues in current lithium-ion batteries is crucial.
• Understanding lithium metal (Li°) electrode behavior in SPEs is vital for SSLMB advancement.

Purpose of the Study:

• To comprehensively investigate the morphological evolution of the Li° electrode within SPEs-based SSLMBs.
• To elucidate the chemical and electrochemical characteristics governing Li° electrode behavior in SPEs.
• To provide insights into dendrite formation and evolution for improved SSLMB stability.

Main Methods:

• Utilized a customized electrochemical cell for in-situ optical microscopic analysis.
• Investigated the morphological changes of the Li° electrode during battery cycling.
• Analyzed the electronic conductivities of interphases formed between Li° and SPEs.

Main Results:

• The elastic nature of SPEs prevents the 'memory effect' in dendrite formation, allowing dissolution and electrolyte occupation.
• Unlike inorganic solid electrolytes, SPEs inhibit secondary dendrite growth by accommodating dissolved lithium.
• Increased electronic conductivities in the Li° electrode/SPE interphases correlate with soft short-circuit behavior during cycling.

Conclusions:

• SPEs offer a unique advantage in mitigating lithium dendrite issues in SSLMBs.
• The findings provide a novel understanding of lithium dendrite dynamics in SPE-based systems.
• This research is critical for enhancing the long-term stability and performance of SSLMBs and related high-energy batteries.