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the high reactivity of both the lithium metal anode (LMA) and Ni-rich NMC usually leads to poor interfacial compatibility with the conventional electrolytes and consequently limited cyclability. [4][5][6][7] Without a sufficiently protective solidelectrolyte interphase (SEI) on LMAs, side reactions between lithium and electrolytes cause lithium dendritic growth and low stripping/plating coulombic efficiency (CE). [8][9][10] At the cathode/electrolyte interface, parasitic electrolyte degradation occurs due to the highly reactive Ni 4+ species generated upon delithiation. This is accelerated by increasing Ni content in the cathode, resulting in limited reversibility of the Ni-rich NMC cathode and thickening of the cathode/electrolyte interphase (CEI) upon cycling. [11,12] Among the strategies proposed to enhance the cyclability of LMBs, electrolyte engineering appears to be one of the most effective and feasible approaches, as the electrolyte plays a keyrole in the CEI and SEI formation. [13][14][15][16][17][18][19] Ionic liquid electrolytes (ILEs), with high electrochemical stability, are valuable options for Li/Ni-rich NMC cells in this context. [20][21][22][23] For instance, Wu et al. [24] have recently reported highly stable cycling of Li/LiNi 0.88 Co 0.09 Mn 0.03 O 2 cells up to 300 cycles with a capacity retention of 88% in [LiTFSI] 0.2 [Pyr 14 FSI] 0.8 (LiTFSI = lithium bis(trifluoromethanesulfonyl)imide, Pyr 14 FSI = N-butyl-Nmethyl pyrrolidinium bis(fluorosulfonyl)imide). Unfortunately, the excellent performance has been only achieved with low cathode mass loading (<5 mg cm −2 ), or/and low current density Lithium metal batteries (LMBs) with nickel-rich cathodes are promising candidates for next-generation, high-energy batteries. However, the highly reactive electrodes usually exhibit poor interfacial compatibility with conventional electrolytes, leading to limited cyclability. Herein, a locally concentrated ionic liquid electrolyte (LCILE) consisting of lithium bis(fluorosulfonyl)imide (LiFSI), 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EmimFSI), and 1,2-difluorobenzene (dFBn) is designed to overcome this challenge. As a cosolvent, dFBn not only promotes the Li + transport with respect to the electrolyte based on the ionic liquid only, but also has beneficial effects on the electrode/electrolyte interphases (EEIs) on lithium metal anodes (LMAs) and LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) cathodes. As a result, the developed LCILE enables dendritefree cycling of LMAs with a coulombic efficiency (CE) up to 99.57% at 0.5 mA cm −2 and highly stable cycling of Li/NMC811 cells (4.4 V) at C/3 charge and 1 C discharge (1 C = 2 mA cm −2 ) for 500 cycles with a capacity retention of 93%. In contrast, the dFBn-free electrolyte achieves lithium stripping/plating CE, and the Li/NMC811 cells' capacity retention of only 98.22% and 16%, respectively under the same conditions. The insight into the coordination structure, promoted Li + transport, and EEI characteristics gives fundamental information essential for fu...

FSI − -based ionic liquids (ILs) are promising electrolyte candidates for longlife and safe lithium metal batteries (LMBs). However, their practical application is hindered by sluggish Li + transport at room temperature. Herein, it is shown that additions of bis(2,2,2-trifluoroethyl) ether (BTFE) to LiFSI-Pyr 14 FSI ILs can effectively mitigate this shortcoming, while maintaining ILs′ high compatibility with lithium metal. Raman spectroscopy and small-angle X-ray scattering indicate that the promoted Li + transport in the optimized electrolyte, [LiFSI] 3 [Pyr 14 FSI] 4 [BTFE] 4 (Li 3 Py 4 BT 4 ), originates from the reduced solution viscosity and increased formation of Li + -FSI − complexes, which are associated with the low viscosity and non-coordinating character of BTFE. As a result, Li/LiFePO 4 (LFP) cells using Li 3 Py 4 BT 4 electrolyte reach 150 mAh g −1 at 1 C rate (1 mA cm −2 ) and a capacity retention of 94.6% after 400 cycles, revealing better characteristics with respect to the cells employing the LiFSI-Pyr 14 FSI (operate only a few cycles) and commercial carbonate (80% retention after only 218 cycles) electrolytes. A wide operating temperature (from −10 to 40 °C) of the Li/Li 3 Py 4 BT 4 /LFP cells and a good compatibility of Li 3 Py 4 BT 4 with LiNi 0.5 Mn 0.3 Co 0.2 O 2 (NMC532) are demonstrated also. The insight into the enhanced Li + transport and solid electrolyte interphase characteristics suggests valuable information to develop IL-based electrolytes for LMBs.The ORCID identification number(s) for the author(s) of this article can be found under

In the presence of trivalent cations, negatively charged globular proteins show a rich phase behaviour including reentrant condensation, crystallisation, clustering and lower critical solution temperature metastable liquid-liquid phase separation (LCST-LLPS). Here, we present a systematic study on how different multivalent cations can be employed to tune the interactions and the associated phase behaviour of proteins. We focus our investigations on the protein bovine serum albumin (BSA) in the presence of HoCl 3 , LaCl 3 and YCl 3 . Using UV-Vis spectroscopy and small-angle X-ray scattering (SAXS), we find that the interprotein attraction induced by Ho 3+ is very strong, while the one induced by La 3+ is comparatively weak when comparing the data to BSA-Y 3+ systems based on our previous work. Using zeta potential and isothermal titration calorimetry (ITC) measurements, we establish different binding affinities of cations to BSA with Ho 3+ having the highest one. We propose that a combination of different cation features such as radius, polarisability and in particular hydration effects determine the proteinprotein interaction induced by these cations. Our findings imply that subtle differences in cation properties can be a sensitive tool to fine-tune protein-protein interactions and phase behaviour in solution.

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The interior of living cells is a dense and polydisperse suspension of macromolecules. Such a complex system challenges an understanding in terms of colloidal suspensions. As a fundamental test we employ neutron spectroscopy to measure the diffusion of tracer proteins (immunoglobulins) in a cell-like environment (cell lysate) with explicit control over crowding conditions. In combination with Stokesian dynamics simulation, we address protein diffusion on nanosecond time scales where hydrodynamic interactions dominate over negligible protein collisions. We successfully link the experimental results on these complex, flexible molecules with coarse-grained simulations providing a consistent understanding by colloid theories. Both experiments and simulations show that tracers in polydisperse solutions close to the effective particle radius R eff = ⟨R i 3⟩1/3 diffuse approximately as if the suspension was monodisperse. The simulations further show that macromolecules of sizes R > R eff (R < R eff) are slowed more (less) effectively even at nanosecond time scales, which is highly relevant for a quantitative understanding of cellular processes.

Ionic liquids (ILs) have been widely explored as alternative electrolytes to combat the safety issues associated with conventional organic electrolytes. However, hindered by their relatively high viscosity, the electrochemical performances of IL‐based cells are generally assessed at medium‐to‐high temperature and limited cycling rate. A suitable combination of alkoxy‐functionalized cations with asymmetric imide anions can effectively lower the lattice energy and improve the fluidity of the IL material. The Li/Li1.2Ni0.2Mn0.6O2 cell employing N‐N‐diethyl‐N‐methyl‐N‐(2‐methoxyethyl)ammonium (fluorosulfonyl)(trifluoromethanesulfonyl)imide (DEMEFTFSI)‐based electrolyte delivered an initial capacity of 153 mAh g−1 within the voltage range of 2.5–4.6 V, with a capacity retention of 65.5 % after 500 cycles and stable coulombic efficiencies exceeding 99.5 %. Moreover, preliminary battery tests demonstrated that the drawbacks in terms of rate capability could be improved by using Li‐concentrated IL‐based electrolytes. The improved room‐temperature rate performance of these electrolytes was likely owing to the formation of Li+‐containing aggregate species, changing the concentration‐dependent Li‐ion transport mechanism.