Multifunctional Electrolyte Research Articles

Nonflammable, localized high-concentration electrolyte towards a high-safety lithium metal battery

The use of high-concentration electrolytes (HCEs) is a promising way to stabilize the lithium metal anode, but their high viscosity and poor wettability impede good Li-ion diffusion kinetics. More importantly, most electrolytes are still highly flammable that pose safety risks to lithium metal batteries. Introducing diluent in HCEs provides more possibilities for multifunctional electrolyte design. Here we report an ether-based, nonflammable localized high-concentration electrolyte (LHCE), with fire-retardant fluorinated phosphazene as a multifunctional diluent, that provides much better safety and dendrite suppression ability than normal electrolytes and HCEs. The diluent makes the salt anions to dominate the solvation sheath, which weaken the interaction between Li ions and the solvated molecules, lowering the desolvation energy for Li plating and guiding the formation of an inorganic-rich solid electrolyte interphase. As a result, lithium plating/stripping on a Cu foil with such a LHCE has a high average Coulombic efficiency of 97.8% at a high current density and capacity (5 mA/cm2 and 5 mAh/cm2). The assembled full cell has a long cycling stability, even with an ultralow capacity ratio of the negative/positive electrodes of 1.2. This work presents a new strategy for producing practical lithium metal batteries with high safety and excellent stability.

Regulating electrode-electrolyte interphases and eliminating hydrogen fluoride to boost electrochemical performances of Li/NCM811 batteries

Li metal batteries (LMBs) coupled with Ni-rich materials are promising candidates for next-generation high-energy-density lithium batteries. However, due to the inferior stability of cathode/solid-electrolyte interphases (CEI/SEI) and aggressive chemistry of Ni-rich cathode materials, Li metal anode (LMA) and LiPF6-based carbonate electrolytes pose a threat to the achievement of high-energy-density LMBs. Herein, 1-(trimethylsilyloxy)cyclohexene (TMSCH) with functional groups (C=C, Si-O) as a novel multi-functional electrolyte additive is employed to regular the CEI/SEI films on the both Ni-rich cathode materials (LiNi0.8Co0.1Mn0.1O2, NCM811) and LMA surface, and scavenge detrimental hydrogen fluoride (HF) to enhance electrochemical performances of the Li/NCM811 batteries. Furthermore, the theoretical calculation, electrochemical measurements and physical characterizations demonstrate the feasibility and effectiveness of the strategy. Specially, the TMSCH-derived SEI film exhibits a hierarchical structure consisting of an organic-rich outer layer and a LiF-rich inner layer. Accordingly, the microcracks generation of NCM811 secondary particles, transition metal ions dissolution, lithium dendrite growth, parasitic reactions and HF generation of electrolyte are effectively addressed. As a result, with existence of the TMSCH additive, the capacity retention of Li/NCM811 batteries at 1C are remarkably enhanced from 68.2% to 84.9% at 30 °C and 64.2% to 85.8% at 45 °C. Furthermore, the Li/Li symmetric cells with TMSCH can stably cycle over 1000 h at 0.2 mA cm−2 and exhibit super-low overpotential of 75 mV at 1 mA cm−2.

In Situ Construction of Protective Films on Zn Metal Anodes via Natural Protein Additives Enabling High-Performance Zinc Ion Batteries.

The strong activity of water molecules causes a series of parasitic side reactions on Zn anodes in the aqueous electrolytes. Herein, we introduce silk fibroin (SF) as a multifunctional electrolyte additive for aqueous zinc-ion (Zn-ion) batteries. The secondary structure transformation of SF molecules from α-helices to random coils in the aqueous electrolytes allows them to break the hydrogen bond network among free water molecules and participate in Zn2+ ion solvation structure. The SF molecules released from the [Zn(H2O)4(SF)]2+ solvation sheath appear to be gradually adsorbed on the surface of Zn anodes and in situ form a hydrostable and self-healable protective film. This SF-based protective film not only shows strong Zn2+ ion affinity to promote homogeneous Zn deposition but also has good insulating behavior to suppress parasitic reactions. Benefiting from these multifunctional advantages, the cycle life of the Zn||Zn symmetric cells reaches over 1600 h in SF-containing ZnSO4 electrolytes. In addition, by adopting a potassium vanadate cathode, the full cell shows excellent cycling stability for 1000 cycles at 3 A g-1. The in situ construction of a protective film on the Zn anode from natural protein molecules provides an effective strategy to achieve high-performance Zn metal anodes for Zn-ion batteries.

Challenges and Modification Strategies of Ni-Rich Cathode Materials Operating at High-Voltage.

Ni-rich cathode materials have become promising candidates for lithium-based automotive batteries due to the obvious advantage of electrochemical performance. Increasing the operating voltage is an effective means to obtain a higher specific capacity, which also helps to achieve the goal of high energy density (capacity × voltage) of power lithium-ion batteries (LIBs). However, under high operating voltage, surface degradation will occur between Ni-rich cathode materials and the electrolytes, forming a solid interface film with high resistance, releasing O2, CO2 and other gases. Ni-rich cathode materials have serious cation mixing, resulting in an adverse phase transition. In addition, the high working voltage will cause microcracks, leading to contact failure and repeated surface reactions. In order to solve the above problems, researchers have proposed many modification methods to deal with the decline of electrochemical performance for Ni-rich cathode materials under high voltage such as element doping, surface coating, single-crystal fabrication, structural design and multifunctional electrolyte additives. This review mainly introduces the challenges and modification strategies for Ni-rich cathode materials under high voltage operation. The future application and development trend of Ni-rich cathode materials for high specific energy LIBs are projected.

High-Rate, Large Capacity, and Long Life Dendrite-Free Zn Metal Anode Enabled by Trifunctional Electrolyte Additive with a Wide Temperature Range.

Aqueous Zn‐ion batteries (AZIBs) have been recognized as promising energy storage devices due to their high theoretical energy density and cost‐effectiveness. However, side reactions and Zn dendrite generation during cycling limit their practical application. Herein, ammonium acetate (CH3COONH4) is selected as a trifunctional electrolyte additive to enhance the electrochemical performance of AZIBs. Research findings show that NH4 + (oxygen ligand) and CH3COO– (hydrogenligand) with preferential adsorption on the Zn electrode surface can not only hinder Zn anode directly contact with active H2O, but also regulate the pH value of the electrolyte, thus suppressing the parasitic reactions. Additionally, the formed SEI is mainly consisted of Zn5(CO3)2(OH)6 with a high Zn2+ transference number, which could achieve a dendrite‐free Zn anode by homogenizing Zn deposition. Consequently, the Zn||Zn symmetric batteries with CH3COONH4‐based electrolyte can operate steadily at an ultrahigh current density of 40 mA cm–2 with a cumulative capacity of 6880 mAh cm–2, especially stable cycling at −10 °C. The assembled Zn||MnO2 full cell and Zn||activated carbon capacitor also deliver prominent electrochemical reversibility. This work provides unique understanding of designing multi‐functional electrolyte additive and promotes a long lifespan at ultrahigh current density for AZIBs.

Tetrathiafulvalene as a multifunctional electrolyte additive for simultaneous interface amelioration, electron conduction, and polysulfide redox regulation in lithium-sulfur batteries

Numerous efforts can improve reversible capacity and long cycling stability for lithium-sulfur (Li–S) batteries, however, challenges remain in achieving high sulfur utilization and suppressing the shuttle effect, especially for cells with a low electrolyte/sulfur (E/S) ratio. In this research, we utilize tetrathiafulvalene (TTF) as multifunctional catalyst for high-performance Li–S batteries through optimizing electrolyte chemistry for the first time. With TTF additive in electrolyte, it acts as π-electron donor molecule to improve the electron transport of Li2Sx due to the van der Waals interaction, and promote LiNO3 to Li3N to form highly conductive passivation layer on lithium anode (Li-anode). Furthermore, TTF functions as a catalyst to improve the redox kinetics of Li2Sx thus slowing down the “shuttle effect”, improve the utilization of sulfur, and protect the Li-anode. As a result, the cell with TTF exhibits excellent performances with high discharge capacity (1359 mAh g−1 at 0.1C), long-term cycling stability (509 mAh g−1 after 500 cycles at 0.5C), and excellent cycling performance even at low E/S ratio (5.5 μL mg−1) (initial discharge capacity of 1129 mAh g−1 with a capacity decay rate of 0.20% per cycle at 0.1C for 200 cycles).

Anion-Containing Solvation Structure Reconfiguration Enables Wide-Temperature Electrolyte for High-Energy-Density Lithium-Metal Batteries.

The demand for high-energy-density lithium batteries (LBs) that work under a wide temperature range (-40 to 60 °C) has been increasing recently. However, the conventional lithium hexafluorophosphate (LiPF6)-based ester electrolyte with a solvent-based solvation structure has limited the practical application of LBs under extreme temperature conditions. In this work, a novel localized high-concentration electrolyte (LHCE) system is designed to achieve the anion-containing solvation structure with less free solvent molecules using lithium difluorophosphate (LiPO2F2) as a lithium salt, which enables wide-temperature electrolyte for LBs. The optimized solvation structure contributes to the cathode-electrolyte interface (CEI) with abundant LiF and P-O components on the surface of the LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode, effectively inhibiting the decomposition of electrolyte and the dissolution of transition-metal ions (TMIs). Moreover, the weakened Li+-dipole interaction is also beneficial to the desolvation process. Therefore, the 4.3 V Li||NCM523 cell using the modified electrolyte maintains a high capacity retention of 81.0% after 200 cycles under 60 °C. Meanwhile, a considerable capacity of 70.9 mAh g-1 (42.0% of that at room temperature) can be released at an extremely low temperature of -60 °C. This modified electrolyte dramatically enhances the electrochemical stability of NCM523 cells by regulating the solvation structure, providing guidelines for designing a multifunctional electrolyte that works under a wide temperature range.

In Situ Constructing a Stable Solid Electrolyte Interface by Multifunctional Electrolyte Additive to Stabilize Lithium Metal Anodes for Li-S Batteries.

Lithium (Li) metal is considered to be the most promising anode due to the ultrahigh capacity and extremely low electrochemical potential. The tricky thing is that the growth of dendritic Li brings huge safety hazards to Li metal batteries. Herein, we demonstrate cerium nitrate as a multifunctional electrolyte additive to form a stable solid electrolyte interface on the metallic Li anode surface for durable Li-S batteries. The presence of Ce3+ helps to modulate the electroplating/stripping of Li and inhibits the growth of dendritic Li. An excellent cycle life exceeding 1400 h at the current density of 1 mA cm-2 can be realized in symmetric Li||Li cells. In addition, the in situ formed robust solid-electrolyte interface (SEI) layer containing cerium sulfide on the Li anode surface conduces to weaken the reducibility of Li and regulate the electrochemical dissolution/deposition reaction on the Li anode. Surprisingly, by virtue of cerium nitrate additive with a low concentration of 0.03 M, the Li-S batteries can afford a capacity of 553 mA h g-1 at 5 C and a long cycle life at 1 C with a high capacity retention of 70.4%. Therefore, this study provides a novel idea to realize a uniform and dendrite-free Li anode for practical Li-S batteries.

Tailoring electrode-electrolyte interphases to enable the cycling stability of lithium metal batteries with LiNi0.8Co0.1Mn0.1O2 cathode

Rechargeable lithium metal batteries (LMBs) coupling with Ni-rich cathodes are promising high-energy-density electrochemical energy storage devices. However, the growth of Li dendrites and structural degradation of Ni-rich materials, associated with the erratic electrode-electrolyte interphase (EEI) and corrosion of harmful acidic species from the hydrolysis of LiPF6, seriously deteriorate the cycling performance of LMBs with Ni-rich cathodes. Herein, glutaric anhydride (GA) as a multifunctional electrolyte additive is proposed to achieve satisfactory lifespan of LMBs by in situ constructing LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode/Li anode-electrolyte interphases (CEI/AEI), and scavenging corrosive acidic species. The GA-derived CEI/AEI layers are rich in CO species, which can strongly coordinate with the Li anode and delithiated Ni-rich cathode surface. Thus, parasitic reactions of the electrolyte on the aggressive surface of the Ni-rich cathode and Li anode are notably reduced. Furthermore, the problems such as the inner microcrack evolution of NCM811 particles, the growth of Li dendrites and the corrosion of acidic species are well addressed. Consequently, the capacity retention of Li/NCM811 cell is increased from 59.4% to 90.7% after 300 cycles at 1C in the presence of GA, and the Li/Li symmetrical cell with GA exhibits the super-stable cyclic performance of 1400 h at 0.2 mA cm−2.

High-voltage lithium-ion capacitors enabled by a multifunctional phosphite electrolyte additive

Combining the high energy of lithium-ion batteries with the high power and excellent cycling stability of supercapacitors, lithium-ion capacitors (LICs) stand for an emerging hybrid technology for next-generation electrochemical energy storage. Among them, the configuration composed of a battery-type cathode and a capacitor-type anode is advantageous owing to its unnecessity for electrode prelithiation but disadvantageous because of its limited operating voltage. Herein, using triphenyl phosphite (TPPi) as a powerful multifunctional electrolyte additive to not only scavenge electrolyte impurities but also form robust, uniform, and thin cathode/electrolyte interface film on cathode and solid-electrolyte interphase film on anode, we develop high-voltage LICs from a high-potential spinel LiNi0.5Mn1.5O4 cathode and an activated carbon anode. In addition to the important multifunctionalities of TPPi, we modulate the capacity ratio between the cathode and anode and composite the electrodes with carbon nanotubes (CNTs) to enhance the overall performance for our LICs. Therefore, having the synergy from the multifunctionalities of TPPi, capacity modulation between the cathode and anode, and electrode compositing with CNTs, the optimized LIC shows a high operating voltage of 3.45 V, high energy density of 61.6 Wh kg−1, high power density of 52.5 kW kg−1, and long cycle life with a capacity retention of 91.8% after 6000 cycles, outperforming all of its previously reported counterparts having a similar configuration incorporating a battery cathode and a capacitor anode. The rational strategy developed in this work is versatile and should be applicable to other electrode/electrolyte systems for advanced hybrid electrochemical energy storage.

A polyamino acid with zincophilic chains enabling high-performance Zn anodes

A polyamino acid with zincophilic chains is introduced as a multifunctional electrolyte additive for uniform Zn deposition and inhibition of side reactions.

Powerful qua-functional electrolyte additive for lithium metal batteries

Lithium metal batteries (LMBs) have attracted tremendous research attention because of the high theoretical capacity (3860 mAh g−1) and the lowest electrochemical potential (−3.04 V vs. standard hydrogen electrode). However, the Lithium dendrites, forming from plating/stripping processes, cause the excessive consumption of electrolyte and active Li and the puncture on the separator. This limits the commercialization of LMBs. Recently, Ma's group proposed heptafluorobutyric anhydride (HFA) as qua-functional electrolyte additive and verified the protection mechanism from the structure and electrochemical properties. Such results creatively put forward qua-functional electrolyte additive for the improvement of LMBs and provides good experience for the exploration of multi-functional additive, inspiring researchers to explore new multi-functional electrolyte additives in future.

Rechargeable magnesium batteries enabled by conventional electrolytes with multifunctional organic chloride additives

The development of a conventional electrolyte, based on commercially available magnesium (Mg) salts in organic solvents, remains one of the most challenging quests for rechargeable Mg batteries. Conventional electrolytes typically form a passivation layer on Mg metal anode, necessitating the extensive use of inorganic chloride additives such as MgCl2. Herein, for the first time, we introduce an organic chloride, tetrabutylammonium chloride (TBAC), as a multifunctional electrolyte additive for conventional magnesium triflate (Mg(OTf)2)-based electrolytes. TBAC was found to perform three major roles: (1) enhance Mg(OTf)2 dissociation in aprotic solvent, (2) inhibit the reduction of triflate anions through surface-adsorbed TBA+, and (3) act as a chloride source to form Mg complexes and stabilize the Mg anode-electrolyte interface. The novel electrolyte combination of TBAC and Mg(OTf)2 in 1,2-dimethoxyethane exhibits excellent Mg plating/stripping with Coulombic efficiency of 97.7% over 200 cycles at 0.5 mA cm−2 and 0.5 mAh cm-2. Postmortem analysis unveils uniform Mg deposition and stable solid electrolyte interphase formation on Mg anode, which enables reversible cycling with Mo6S8 cathode. Together with our findings on another organic chloride additive, 1-ethyl-3-methylimidazolium chloride, and in combination with different electrolyte salts and solvents, we showcase the general promise of high-performance conventional electrolytes for rechargeable Mg batteries.

Lithium Cyano Tris(2,2,2-trifluoroethyl) Borate as a Multifunctional Electrolyte Additive for High-Performance Lithium Metal Batteries

Lithium cyano tris(2,2,2-trifluoroethyl) borate (LCTFEB) has been synthesized and investigated as a new electrolyte additive for high-performance lithium metal batteries. LCTFEB is prepared by the reaction of tris(2,2,2-trifluoroethyl) borate with lithium cyanide. The incorporation of LCTFEB into a carbonate-based electrolyte has been investigated. The electrochemical performance of NCM523/Li cells and symmetric Li/Li cells is significantly improved upon the incorporation of LCTFEB (5 wt %) into the electrolyte. Various characterizations of the lithium metal morphology and the solid electrolyte interphase (SEI) on the lithium metal anode have been conducted using field-emission scanning electron microscopy, cryogenic transmission electron microscopy, and X-ray photoelectron spectroscopy, suggesting the generation of a thin (∼10 nm) LiF-rich SEI with low concentrations of B and N compounds. The different SEI structures are formed by the preferential reductive decomposition of LCTFEB, resulting in improved electrochemical performance. The new electrolyte additive provides insight into innovative approaches for multifunctional electrolyte additive design.

Dual‐Salt Electrolyte Additives Enabled Stable Lithium Metal Anode/Lithium–Manganese‐Rich Cathode Batteries

Although lithium (Li) metal anode/lithium–manganese‐rich (LMR) cathode batteries have an ultrahigh energy density, the highly active Li metal and structural deterioration of LMR can make the usage of these batteries difficult. Herein, a multifunctional electrolyte containing LiBF4 and LiFSI dual‐salt additives is designed, which enables the superior cyclability of Li/LMR cells with capacity retentions of ≈83.4%, 80.4%, and 76.6% after 400 cycles at 0.5, 1, and 2 C, respectively. The dual‐salt electrolyte can form a thin, uniform, and inorganic species‐rich solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI). In addition, it alleviates the bulk Li corrosion and enhances the structural sustainability of LMR cathode. Moreover, the electrolyte design strategy provides insights to develop other high‐voltage lithium metal batteries (HVLMBs) to enhance the cycle stability.

Isatin anhydride as multifunctional film-forming additive to enhance cycle life of high-voltage Li-ion batteries at elevated temperature

High-voltage Ni-rich based lithium-ion batteries with long-term cycled life can be obtained by reasonable regulation of the nonaqueous electrolyte components. Herein, a novel multifunctional electrolyte additive, isatin anhydride (IAn) is dedicated to construct stable solid-electrolyte-interface (SEI) films on the both Ni-rich layered LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode and graphite anode in a high-voltage pouch cell. Electrochemical tests reveal that IAn can significantly enhance the long-term cycling performance of the graphite/NCM523 full-cell at high voltage and high temperature. The pouch cell containing 1.0 wt% IAn shows an excellent capacity retention of 92.3% after 200 cycles between 3.0 and 4.5 V at 1.0C under 45 °C condition. In contrast, the cell without IAn appears a lower cycle performance after 192 cycles while the capacity retention decrease to 18.3%. Such obvious improvement of electrochemical performance contributes from the formation of thin and stable SEI films at two electrodes’ surfaces, leading to restraining the electrolyte decomposition and protecting material structures on the both cathode and anode.

A New Fluorinated Sultone as Multifunctional Electrolyte Additive for High‐Performance LiCoO2/Graphite Cell

AbstractThe energy density of lithium cobalt oxide (LiCoO2)‐based cells can be increased by charging at voltages above 4.2 V. However, the poor interface stability of the cathode/electrolyte deriving from the continuous severe decomposition of the electrolyte on the cathode/electrolyte surface and the instability of the structure of the cathode at high‐voltage operation limits their wider commercial application. Herein, a new fluoro‐functionalized electrolyte additive, tetrafluoroethane beta‐sultone (TFBS), is used for promoting the electrochemical performance of LiCoO2‐based cells. Upon cycling between 3.0 and 4.5 V (vs. Li/Li+) with 0.5 C (1 C=274.4 mAh/g), it is shown that the capacity retention of the LiCoO2/graphite pouch‐cell with TFBS‐controlled electrolyte reaches 96.8 % (183.9 mAh g−1), yet it is 66.5 % (126.3 mAh g−1) for the pouch‐cell without TFBS in baseline electrolyte at the 100th cycle. All the results indicate that TFBS can be decomposed prior to the solvents in the electrolyte and can then form low‐resistance, high‐conductivity interface layers on the surfaces of the cathode‐electrolyte and the anode‐electrolyte, respectively, thus improving the cycling stability of the cells at a high charging cutoff voltage (4.5 V).

High-voltage and high-safety nickel-rich layered cathode enabled by a self-reconstructive cathode/electrolyte interphase layer

To achieve widespread adoption of Ni-rich layered oxides in commercial applications, it is highly necessary to address their cyclic stabilities and safety aspects under prolonged and harsh operating conditions, which will aggravate the simultaneous degradation of the Ni-rich cathode and electrolyte due to the more serious interfacial side reactions between them. Herein, a self-reconstructive cathode/electrolyte interphase (CEI) layer with good interfacial stability was designed and constructed for Ni-rich cathode, through the incorporation of dendritic mesoporous silica (DMS) with rich surface silicon-hydroxyl groups as a multifunctional electrolyte additive. The DMS shows the ability to reconstruct the CEI layer in real time, i.e., endowing the CEI layer with defluorination function, spontaneously formed LiPO2F2, and in-situ formed anti-fluorination protective layer with enhanced electron and Li+ diffusion. As expected, the sample with a self-reconstructive CEI layer exhibits significantly superior cyclic stability compared to the pristine one under extended cut-off voltage (4.5 V) or elevated temperature (55°C). Notably, the flame-retardant effect of DMS additive can also contribute towards the thermal stability of the electrolyte and electrode, which will effectively improve the safety aspect of the battery. Thus, this work provides new insights into reducing undesired self-reinforced failure process in Ni-rich cathode and reconstructing a self-healing CEI layer for high-safety, high-voltage lithium-ion batteries.

Enhanced Safety and Performance of High-Voltage Solid-State Sodium Battery through Trilayer, Multifunctional Electrolyte Design

Solid-state electrolytes are promising to resolve the safety hazards and low energy density of traditional liquid batteries. However, the practical application of these electrolytes has been impaired by the low ionic conductivity and an unstable interface present with a high-voltage cathode. Here, an improvement of ionic conductivity, interface, and safety was achieved by impregnating anti-oxidation polyacrylonitrile (PAN) and anti-reduction poly(ethylene oxide) (PEO) into a sandwich sodium superionic conductor (NASICON) framework with a dense core and porous outer layers. Using this sandwich composite electrolyte (SCE), a high ionic conductivity of 4.13×10−4 S cm−1 at 30°C was obtained owing to long-range and continuous ionic conduction pathways in the porous network. The interfacial resistance was greatly improved through the creation of a compact and stable interface. More importantly, the safety of this SCE is improved through the in-situ formation of a central, dense NASICON layer, which suppressed dendrite growth. Furthermore, a high-voltage solid-state battery combining Na3V2(PO4)2F3 (NVPF) with this SCE exhibited an impressive rate performance with long cycle life. This study offers a promising strategy to design ultra-safe, high energy density, solid-state batteries.

Cross-Talk-Suppressing Electrolyte Additive Enabling High Voltage Performance of Ni-Rich Layered Oxides in Li-Ion Batteries.

Control of electrode-electrolyte interfacial reactivity at high-voltage is a key to successfully obtain high-energy-density lithium-ion batteries. In this study, 2-aminoethyldiphenyl borate (AEDB) is investigated as a multifunctional electrolyte additive in stabilizing surface and bulk of both Ni-rich LiNi0.85 Co0.1 Mn0.05 O2 (NCM851005) and graphite electrodes in a cell operated with elevated upper cutoff voltage of 4.4 V vs. Li+ /Li. The presence of AEDB in a full-cell inhibits structural degradation of both cathode and anode materials, suppressing crack formation, and reduces metal dissolution at the cathode and metal deposition at the anode. As a consequence, the interfacial resistance is significantly reduced. Moreover, this is a case where "the whole is greater than the sum of the parts": the effect of AEDB in half-cells is rather modest, whereas in full-cells its addition results in tremendous performance improvement. The graphite‖NCM851005 full-cell in the presence of AEDB has a capacity retention of 88 % after 100 cycles, even when the upper cutoff voltage is set to 4.35 V, corresponding to 4.4 V vs Li+ /Li, whereas with standard electrolyte under the same conditions it is only 21 %. The study shows a simple and easy approach to using Ni-rich cathodes in an extended voltage window and demonstrates the importance of full-cell testing for electrolyte additive selection.