In the fast-evolving world of technology, the demand for high-performance lithium-ion batteries (LIBs) is constantly on the rise. These batteries are the powerhouse behind numerous electronic devices such as computers, communication devices, and consumer electronics. To keep up with the increasing consumer demands, LIBs need to possess higher energy density, longer cycling life, faster-charging capability, and a broader operating temperature range. One primary component of LIBs is the cathode material, with LiCoO2 (LCO) being the most commonly used.
Despite the widespread use of LCO, current advanced electrolytes are unable to meet the requirements for high energy density and fast-charging performance in LIBs. The continuous oxidative decomposition of electrolytes, non-uniform cathode-electrolyte interphase growth, and sluggish interfacial kinetics hinder the achievement of high voltage and fast charging in batteries. These challenges call for innovative solutions to enhance the stability and efficiency of LIBs.
A groundbreaking research study led by Prof. Wu Zhongshuai from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) introduced a novel universal additive-containing “cocktail electrolyte” to address the limitations of current electrolytes. This innovative FPE electrolyte, based on the synergistic cooperation of multi-component additives, enabled commercial LCO to operate at high voltage (4.6 V) and ultra-fast charging (5 C) across a wide temperature range (-20 to 45o C). Moreover, it exhibited compatibility with high-Ni and Co-free cathodes, showcasing its versatility in battery applications.
The collaborative effort of multiple components in the FPE electrolyte resulted in the formation of robust and kinetically efficient electrode/electrolyte interphases on both the cathode and anode of the battery. These interphases, enriched with LiF and Li3PO4, displayed exceptional mechanical stability and enhanced ionic conductivity. As a result, they prevented cathode surface degradation, minimized unwanted interfacial reactions, accelerated reaction kinetics, and inhibited the formation of lithium dendrites even under high current densities. This led to the development of a high-performance 4.6 V Li-ion battery with outstanding cycling stability.
The research findings demonstrated that the capacity retention in batteries using FPE electrolyte reached an impressive 73.2% even at 5 C over 1,000 cycles. In practical pouch-type cells, the graphite||LCO battery maintained up to 72.1% capacity retention after 2,000 cycles and exhibited long-term cyclability over 3,800 cycles. Furthermore, the study highlighted the broad applicability of FPE in high-voltage Ni-rich and Co-free cathodes, indicating a promising future for high-energy-density and fast-charging batteries. Prof. Wu emphasized that this work offers a practical strategy to revolutionize battery technology.
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