Interfacial stabilization enabled by triethyl borate for high-voltage batteries with a wide temperature range

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Ultrahigh-nickel LiNi_0.9Co_0.05Mn_0.05O₂ (NCM90) cathodes paired with lithium metal anodes offer high energy density.
• Parasitic reactions at the electrode/electrolyte interface limit the practical application of these high-energy-density batteries.

Purpose of the Study:

• To investigate the efficacy of triethyl borate (TEB) as a novel electrolyte additive for Li‖NCM90 batteries.
• To enhance the electrochemical performance and interfacial stability of high-energy-density batteries.

Main Methods:

• Incorporation of triethyl borate (TEB) as a multifunctional electrolyte additive in Li‖NCM90 cells.
• Electrochemical performance evaluation under high cut-off voltage (4.6 V) and wide temperature range (-30 °C to 50 °C).
• Analysis of interfacial properties through the formation of cathode-electrolyte interphase (CEI) and solid electrolyte interphase (SEI).

Main Results:

• TEB additive effectively scavenges HF, suppressing transition metal dissolution and stabilizing the interface.
• Formation of compact, conductive B-O/B-F-rich CEI and SEI layers accelerates Li⁺ transport and inhibits dendrite growth.
• Li‖NCM90 cells with TEB achieved high initial capacity (214.45 mAh g^-1 at 4.6 V, 2C), stable cycling (>200 cycles), and excellent performance at extreme temperatures (-30 °C and 50 °C).

Conclusions:

• Triethyl borate is a promising electrolyte additive for enhancing the performance and stability of high-energy-density Li‖NCM90 batteries.
• The TEB additive strategy facilitates the development of advanced batteries with improved safety and operational range.
• This approach offers a viable pathway for the practical realization of next-generation energy storage solutions.