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The electrolyte chemistry is crucially important for promoting the practical application of lithium metal batteries (LMBs). Here, we demonstrate for the first time that 1,3‐dimethylimidazolium dimethyl phosphate (DIDP) and trimethylsilyl trifluoroacetate (TMSF) can undergo in situ transesterification in carbonate electrolyte to generate dimethyl trimethylsilyl phosphate (DTMSP) and 1,3‐dimethylimidazolium trifluoroacetate (DITFA) as multifunctional additives for LMBs. H2O and HF can be removed by the Si−O group in DTMSP to improve the moisture resistance of electrolyte and the stability of cathode. Furthermore, the dissolution of lithium nitrate (LiNO3) in carbonate electrolyte can be promoted by the trifluoroacetate anion (TFA−) in DITFA, thereby optimizing the solvation structure and transport kinetics of Li+. More importantly, both DTMSP and DITFA tend to preferential redox decomposition due to the low lowest unoccupied molecular orbital (LUMO) and high highest occupied molecular orbital (HOMO). Consequently, a thin and robust layer rich in P/N/Si on the cathode and an inorganic‐rich layer (e.g. Li3N/Li3P) on the anode can be constructed and superior electrochemical performances are achieved. This artificial transesterification strategy to introduce favorable additives paves an efficient and ingenious route to high‐performance electrolyte for LMBs. [ABSTRACT FROM AUTHOR]

The carbonate electrolyte chemistry is a primary determinant for the development of high‐voltage lithium metal batteries (LMBs). Unfortunately, their implementation is greatly plagued by sluggish electrode interfacial dynamics and insufficient electrolyte thermodynamic stability. Herein, lithium trifluoroacetate‐lithium nitrate (LiTFA−LiNO3) dual‐salt additive‐reinforced carbonate electrolyte (LTFAN) is proposed for stabilizing high‐voltage LMBs. We reveal that 1) the in situ generated inorganic‐rich electrode‐electrolyte interphase (EEI) enables rapid interfacial dynamics, 2) TFA− preferentially interacts with moisture over PF6− to strengthen the moisture tolerance of designed electrolyte, and 3) NO3− is found to be noticeably enriched at the cathode interface on charging, thus constructing Li+‐enriched, solvent‐coordinated, thermodynamically favorable electric double layer (EDL). The superior moisture tolerance of LTFAN and the thermodynamically stable EDL constructed at cathode interface play a decisive role in upgrading the compatibility of carbonate electrolyte with high‐voltage cathode. The LMBs with LTFAN realize 4.3 V‐NCM523/4.4 V‐NCM622 superior cycling reversibility and excellent rate capability, which is the leading level of documented records for carbonate electrode. [ABSTRACT FROM AUTHOR]

Solid‐state electrolytes hold great promise for lithium‐based batteries with high energy density and safety. Here, novel metal‐organic frameworks (MOFs) based composite membranes were fabricated by a rolling process and subsequently employed as quasi solid‐state electrolytes, exhibiting improved ionic conductivity and Li+ transference number as well as stable electrochemical window. Furthermore, the MOF‐based membranes presented a significant effect in modulating the stripping/plating process of Li and resulted in a dendrite‐free Li deposition. The corresponding LiFePO4|Li batteries were assembled and presented improved rate capability and high Coulombic efficiency, offering a new option for MOF‐based electrolytes. [ABSTRACT FROM AUTHOR]

The regulation of lithium plating/stripping behavior is considered to be critical for next-generation safe and high-energy-density lithium metal batteries. Lithium deposition with maximum granular size and minimum microstructural tortuosity can significantly improve the lithium plating/stripping efficiency. Here, a self-assembled organosilane layer with nanopores is constructed on Cu current collector surface via a thiol-Cu reaction. In contrast to typical stacked-particle morphology with small grain size and high specific area in ether electrolyte, dough-like and lateral-growth lithium deposition can be plated on the modified Cu current collector due to the low surface energy of a lithiophilic Si-O-Si membrane. The planar and dense lithium deposition contributes to the stable implementation of up to near 500 cycles in full cells with high-loading LiFePO4 cathode. Anticorrosion in rigorous Cl-ion containing solution can even be achieved due to the corrosive repellency of hydrophobic organosilane. A high Coulombic efficiency (97.12%) is remained after corroding for 300 min. Moreover, the irreversible capacity loss caused by galvanic corrosion, an ignored but crucial aspect, has been significantly suppressed due to the passivation of high-redox-potential Cu by organosilane coating. [ABSTRACT FROM AUTHOR]

The performance of lithium batteries is heavily governed by the transport of ions within the electrolytes. Commercial liquid electrolytes, however, generally exhibit a low lithium‐ion transference number, causing concentration polarization, side reactions, and deteriorated battery performance. Herein, a novel class of electrolyte additives based on particles of metal–organic framework is proposed to immobilize the anions while allowing efficient transport of lithium ions in the electrolytes. The use of such additives effectively increases the lithium‐ion transference number, enhances the rate capability, and prolongs the cycling life, which provides a facile yet effective strategy toward lithium batteries with dramatically improved performances. [ABSTRACT FROM AUTHOR]

A triple-function eutectic solvent additive of N-methylacetamide (NmAc) with LiNO 3 is proposed to enhance the stability and compatibility of carbonate electrolyte. The designed electrolyte effectively manipulates Li+ solvation structure, reduces the generation of highly corrosive HF and constructs stable and flexible interphase layers on both electrodes. [Display omitted] Rational carbonate electrolyte chemistry is critical for the development of high-voltage lithium metal batteries (LMBs). However, the implementation of traditional carbonate electrolyte is greatly hindered by the generation of an unstable electrode interphase and corrosive by-product (HF). Herein, we propose a triple-function eutectic solvent additive of N -methylacetamide (NmAc) with LiNO 3 to enhance the stability and compatibility of carbonate electrolyte. Firstly, the addition of NmAc significantly improves the solubility of LiNO 3 in carbonate electrolyte by forming an eutectic pair, which regulates the Li+ solvation structure and leads to dense and homogenous Li plating. Secondly, the hydrolysis of acidic PF 5 is effectively alleviated due to the strong complexation of NmAc with PF 5 , thus reducing the generation of corrosive HF. In addition, the optimized cathode electrolyte interphase layer decreases the structural degradation and transition metal dissolution. Consequently, Li||LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622) cells with the designed electrolyte deliver superior long-term cycle reversibility and excellent rate capability. This study unveils the rationale for incorporating eutectic solvent additives within carbonate electrolytes, which significantly contribute to the advancement of their practical application for high-voltage LMBs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Low-solubility LiNO 3 and K 2 B 4 O 5 (OH) 4 were introduced into carbonate electrolyte via metal–organic frameworks (MOFs) nanocapsules. • Sustainable release of LiNO 3 and K 2 B 4 O 5 (OH) 4 can participate in the formation of stable electrolyte interphase during battery cycling. • The Li||NCM523 and Li||NCM622 cells with nanocapsules in electrolyte deliver superior cycling stability and capacity retention. Constructing robust electrolyte interphase through inorganic electrolyte additives is an effective strategy to improve the electrochemical performance of lithium metal batteries (LMBs). However, the limited solubility of such additives in electrolyte hinders their further application. Herein, we apply metal–organic frameworks (MOFs) as nanocapsules to sustainably release lithium nitrate (LiNO 3) and a novel salt of potassium tetraborate (K 2 B 4 O 5 (OH) 4). LiNO 3 is inclined to undergo reduction on lithium anode to form a nitride-rich solid electrolyte interphase (SEI) layer; while K 2 B 4 O 5 (OH) 4 preferentially decomposes on high-voltage cathodes to create a boron-rich cathode electrolyte interphase (CEI) layer. Although both salts exhibit poor solubility in commercial carbonate electrolyte, they can be continuously consumed on the electrode surface and concurrently replenished from the nanocapsules during long-term cycling process. As a result, a compact lithium deposition is achieved and the dissolution of transition metals is restrained. Upon the sacrifice of LiNO 3 and K 2 B 4 O 5 (OH) 4 , the lifespan of LMBs is remarkbly improved. The Li||LiNi 0.5 Co 0.2 Mn 0.3 (NCM523) cells at 4.3 V and Li||LiNi 0.6 Co 0.2 Mn 0.2 (NCM622) cells at 4.4 V can respectively deliver high capacity retentions of 87 % and 80.1 % for 200 cycles. [ABSTRACT FROM AUTHOR]

Lithium metal batteries (LMBs) are considered as the most promising high-energy storage devices due to the high specific capacity and the lowest reduction potential of lithium (Li) metal anode. However, the uncontrolled Li dendrite growth, structural collapse of cathode and electrolyte oxidation significantly limit the practical applications of LMBs in terms of high voltage or rapid charge-discharge operation. Herein, an advanced carbonate-based electrolyte is rationally designed by adding lithium difluoro(oxalato)borate-tris(trimethylsilyl)borate (LiDFOB-TMSB) dual additives. Density functional theory (DFT) calculations and experiments reveal that unique dual additives work synergistically to form robust solid electrolyte interphases on the anode and cathode. Implementation of such dual additives can suppress Li dendrite formation, improve the compatibility of electrode-electrolyte interphases, and enhance the structural stability of LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) at high-voltage of 4.4 V. The dual-additive electrolyte enables Li||Cu cell to achieve a high average coulombic efficiency (CE) of 97.7 % at the current density of 1 mA cm−2 with an areal capacity of 1 mAh cm−2 and Li||NCM523 cell to deliver 74.4 % retention at 1 C and a cut-off voltage 4.4 V after 300 cycles. This work provides an effective dual-additive strategy for the feasibility of high-voltage LMBs towards the practical application. [Display omitted] • A dual-additive electrolyte with LiDFOB-TMSB is proposed. • The combination of TMSB and PF 6 − inhibits the transfer of PF 6 −. • TMSB-PF 6 − and LiDFOB preferentially decompose at the cathode to form a robust CEI. • LiDFOB preferentially decomposes at the anode to form a robust SEI film. • TMSB-PF 6 − can inhibit the reaction between PF 6 − and the Li anode. [ABSTRACT FROM AUTHOR]

[Display omitted] • Anionic MOF modified separator is applied to alleviate concentration polarization. • The thermal stability of modified separator is significantly improved. • The negatively charged ligands of MOF electrostatically repel anions. • The modified separator facilitates the transport of Li+ with a t Li + of 0.82. Low lithium ion (Li+) mobility and thermal stability of polyolefin separator are crucial obstacles that limit the utilization of Li metal electrodes in the age of rapid acceleration toward high-energy-density rechargeable batteries. Herein, we report anionic metal-organic frameworks (MOFs) modified separator to overcome the barriers. By grafting –SO 3 − group onto the Universitetet i Oslo (UIO) structure, the anionic MOFs nanoparticles are synthesized (noted as UIO-SOLi). The UIO-SOLi is adhered on the surface of Celgard 2400 via polyacrylic acid (PAA) to fabricate the modified separator (UIOSOL@PP). The MOFs coating optimizes the wettability and thermal stability of the pristine separator. Negatively charged moieties –SO 3 − within the pore surface electrostatically repel anions while facilitate the transport of Li+, thus achieving a high Li+ transference number (t Li +) of 0.82. The effective Li+ transport relieves the concentration polarization, regulates the Li+ flow and realizes the uniform deposition of lithium. By implementing the UIOSOL@PP separator, the LiFePO 4 |Li cells deliver superior rate performance and cycling lifespan that renders a high discharge capacity retention of 155 mAh g−1 over 600 cycles at 1C. These results indicate that anionic MOFs modified separator is a promising strategy to modulate Li+ flow and assist with efficient long-term operation of lithium metal batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Rare earth nitrates were firstly utilized as the carbonate electrolyte additives. • The rare earth ion changes the solvation structure of the lithium ion. • The interphase with rare earth nitrates is favorable for the dense Li deposition. • Stable cycling and high Coulombic efficiency can be achieved. Lithium metal is recognized as the next generation anode material due to its ultra-high capacity. However, the safety hazards caused by the dendritic lithium growth hinder its practical application. In this work, rare earth nitrates, such as Y(NO 3) 3 , are introduced as electrolyte additives because of the unfixed coordination number and complex coordination configuration for rare earth cations. Molecular dynamics simulation reveals that the rare earth ion changes the solvation structure of the lithium ion. When it is combined with fluoroethylene carbonate (FEC), the interphase generated from electrochemical reactions is favorable for the dense Li deposition. As a result, a stable and high Coulombic efficiency is achieved for Li/Cu cells in commercial carbonate electrolyte with such additive. The Li/Li symmetrical cells can operate>1000 h at current density of 1 mA cm−2. Moreover, the NCM811/Li full cells deliver superior cycling stability and better rate performance. This strategy sheds light on utilizing rare earth elements to optimize the electrolyte for lithium metal anode and it can be extended to other electrolytes aiming at sodium and potassium battery chemistry. [ABSTRACT FROM AUTHOR]