Lithium Nitrate Solvation Chemistry in Carbonate Electrolyte Sustains High‐Voltage Lithium Metal Batteries

Abstract

The lithium metal anode is regarded as apromising candidate in next-generation energy storage devices.L ithium nitrate (LiNO 3 )i sw idely applied as an effective additive in ether electrolyte to increase the interfacial stability in batteries containing lithium metal anodes.However,because of its poor solubility LiNO 3 is rarely utilized in the high-voltage window provided by carbonate electrolyte.D issolution of LiNO 3 in carbonate electrolyte is realized through an effective solvation regulation strategy.L iNO 3 can be directly dissolved in an ethylene carbonate/diethyl carbonate electrolyte mixture by adding trace amounts of copper fluoride as ad issolution promoter.L iNO 3 protects the Li metal anode in aw orking high-voltage Li metal battery.W hen aL iNi 0.80 Co 0.15 Al 0.05 O 2 cathode is paired with aL im etal anode,a ne xtraordinary capacity retention of 53 %i sa chieved after 300 cycles (13 % after 200 cycles for LiNO 3 -free electrolyte) and av ery high average Coulombic efficiency above 99.5 %i sa chieved at 0.5 C. The solvation chemistry of LiNO 3 -containing carbonate electrolyte may sustain high-voltage Li metal anodes operating in corrosive carbonate electrolytes.Securing long battery life between charges is al ong-term pursuit in mobile energy storage devices with high energy density. [1] Lithium-ion batteries-one of the most mature and widely adopted energy storage devices-are now approaching at heoretical energy density limit. Therefore,a lternative strategies are needed to meet the increasing demands of portable electronics,e lectric vehicles,a nd grid-scale energy storage. [2] Lithium metal batteries (LMBs), which contain ahigh-voltage cathode and Li metal anode,outperform other candidates because they possess an ultrahigh theoretical specific capacity (3860 mAh g À1 )a nd the lowest reduction potential (À3.04 Vv s. standard hydrogen electrode (SHE)) among Li metal anodes. [3,4] Nevertheless,s evere problems impede the practical application of high-voltage LMBs-and particularly Li metal anodes,w hich first appeared in the 1970s. [5] Instead of forming uniform deposits,L it ends to adopt dendritic morphology during electrodeposition because of non-uniform current/ion distributions. [6] Li dendrites commonly lead to the formation of unstable solid electrolyte interfaces (SEI), low Coulombic efficiency (CE) because of high chemical reactivity,a nd even severe safety hazards when the separator is penetrated. [7,8] Theu nstable SEI can further aggravate dendrite growth, finally leading to rechargeable batteries with apoor lifespan. Therefore,stabilizing the Li interface is required to ensure that LMBs are practically viable.Spontaneous reactions between Li metal and electrolyte generate SEI, [7] and regulating the properties of the SEI by altering the electrolyte components is af acile and feasible approach. Lithium nitrate (LiNO 3 ), with ah igh solubility in ether solvent (typically 5wt% in dimethoxyethane and 1,3-dioxolane) is regarded as ac ritical electrolyte additive in lithium-sulfur (Li-S)...

Cation−Solvent, Cation−Anion, and Solvent−Solvent Interactions with Electrolyte Solvation in Lithium Batteries

“…The cluster-based DFT calculations were performed in Gaussian (G09) [15] suite of program with Becke's three-parameter hybrid method using the LeeÀYangÀParr correlation functional (B3LYP). [16] The geometrical structures and the vibrational modes were calculated at 6-311 + +G(d, p) level.…”

Hierarchical Co3O4 Nanofiber–Carbon Sheet Skeleton with Superior Na/Li‐Philic Property Enabling Highly Stable Alkali Metal Batteries

“…Over the past 4 decades, various modification methods have been applied to tackle these obstructive problems. In consideration of the poor mechanical property and chemical instability of original SEI layer, surface modification is carried out to enhance the SEI formation and suppress dendrite growth through electrolyte regulation (Cs + , Li halide, LiNO 3 , and NaAlCl 4 ·2SO 2 ), artificial SEI layer (LiPON, atomic Al 2 O 3 layer deposition, Nafion‐LiCl, 1,4‐dioxacyclohexane (DOX), phosphorene), and concentrated electrolyte (concentrated NaFSI‐glyme, 4 m LiTFSI), etc. However, due to the “hostless” characteristics of the alkali metal electrode, this kind of method cannot withstand the large volume change generated during the cycling and eventually lead to the rupture of the SEI film.…”

Ion association tailoring SEI composition for Li metal anode protection

“…Among them, lithium nitrate (LiNO 3 ) is a highly efficient electrolyte additive in lithium metal batteries and has been intensively studied in recent years [18][19][20] . As a donor of LiNO 2 , LiN x O y and other substances with high lithium ion conductivity [21] , LiNO 3 can thus accelerate the transmission of Li + in SEI.…”