Synthesizing an inorganic-rich solid electrolyte interphase by tailoring solvent chemistry in carbonate electrolyte for enabling high-voltage lithium metal batteries

High-voltage(>4.0 V)lithium metal battery(LBM)is considered to be one of the most promising candidates for next-generation high-energy batteries.However,the commercial carbonate electrolyte delivers a poor compatibility with Li metal anode,and its organic dominated solid electrolyte interphase(SEI)shows a low interfacial energy and a slow Li^(+)diffusion ability.In this work,an inorganic LiF-Li_(3)N rich SEI is designed to enable high-voltage LBM by introducing nano-cubic LiF and LiNO_(3)into1 M LiPF_(6)ethylene carbonate(EC)/dimethyl carbonate(DMC)(v:v=1:1)electrolyte.Specifically,the unique nano-cubic structure of as-synthetized LiF particles achieves its high concentration dissolution in carbonate electrolyte to enhance the interfacial energy of SEI.In addition,tetramethylene sulfolane(TMS)is used as a carrier solvent to dissolve LiNO_(3)in the carbonate electrolyte,thereby deriving a Li_(3)N-rich SEI.As a result,the as-designed electrolyte shows a high average Li plating/striping CE of 98.3%after 100 cycles at 0.5 m A cm^(-2)/0.5 mA h cm^(-2).Furthermore,it also enables the ultrathin Li(~50μm)‖LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM,4.4 mA h cm^(-2))full cell to deliver a high-capacity retention of 80.4%after 100 cycles with an outstanding average CE of 99.7%.Notably,the practical application prospect of the modified electrolyte is also estimated in LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)‖Li pouch cell with an energy density of 261.2 W h kg^(-1).This work sheds light on the internal mechanism of Li^(+)transport within the inorganic dominated SEI and provides a simple approach to stabilize the high-voltage LMBs.

Stable lithium metal anode enabled by a robust artificial fluorinated hybrid interphase

One of the key challenges for achieving stable lithium(Li) metal anode is the construction of the rational solid electrolyte interphase(SEI),but its realization still faces enormous challenges.In this work,a robust artificial fluorinated hybrid interphase consisting of lithium-bismuth(Li3Bi) alloy and lithium-fluoride(LiF) was designed to regulate Li deposition without Li dendrite growth.The obtained hybrid interphase showed the high Li+diffusion rate(3.5 × 10^(-4)S cm^(-1)),high electron resistivity(9.04 × 10^(4)Ω cm),and high mechanical strength(1348 MPa),thus enabling the uniform Li deposition at the Li/SEI interface.Specifically,Li3Bi alloy,as a superionic conductor,accelerated the Li+transport and stabilized the hybrid interphase.Meanwhile,LiF was identified as a superior electron-blocker to inhibit the electron tunneling from the Li anode into the SEI.As a result,the modified Li anode showed the stable Li plating/stripping behaviors over 1000 cycles even at 20 mA cm^(-2).Moreover,it also enabled the Li(50 μm)‖LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(4.4 mA h cm^(-2)) full cell to achieve an average Coulombic efficiency(CE) of 99.6%and a high-capacity retention of 79.2% after 100 cycles,whereas the bare Li anode only exhibited a low-capacity retention of 8.0%.This work sheds light on the internal mechanism of Li+transport within the hybrid interface and provides an effective approach to stabilize the interface of Li metal anode.