We report a low-cost water-in-salt electrolyte (WiSE), of 30 m ZnCl ₂ , which enables a dendrite-free Zn metal anode to possess a high coulombic efficiency.

A great challenge for all aqueous batteries, including Zn‐metal batteries, is the parasitic hydrogen evolution reaction on the low‐potential anode. Herein, we report the formula of a highly concentrated aqueous electrolyte that mitigates hydrogen evolution by transforming water molecules more inert. The electrolyte comprises primarily ZnCl₂ and LiCl as an additive, both of which are inexpensive salts. The O–H covalent bonds in water get strengthened in a chemical environment that has fewer hydrogen bonding interactions and a greater number of Zn–Cl superhalides, as suggested by integrated characterization and simulation. As a result, the average Coulombic efficiency of zinc‐metal anode is raised to an unprecedented >99.7% at 1 mA cm⁻². In the new electrolyte, the plating/stripping processes leave the zinc‐metal anode dendrite‐free, and the zinc‐metal anode delivers stable plating/stripping cycles for 4000 hours with an areal capacity of 4 mAh cm⁻² at 2 mA cm⁻². Furthermore, the high Coulombic efficiency of zinc‐metal anode in the ZnCl₂‐LiCl mixture electrolyte is demonstrated in full cells with a limited anode. The V₂O₅·H₂O||Zn full cell with an N/P mass ratio of 1.2 delivers a stable life of more than 2500 cycles, and the LiMn₂O₄||Zn hybrid cell with an N/P mass ratio of 0.6 exhibits 1500 cycles in its stable life.

The two nitrile groups at the wings of the nonnucleoside HIV-1 reverse transcriptase (RT) inhibitor TMC278 are both identified in high-sensitivity 2D IR spectroscopy experiments of the HIV-1 RT/TMC278 complex. The vibrational spectra indicate that the two arms of the inhibitor sense quite different environments within the hydrophobic pocket. The vibrational relaxation of the two arms are almost equal at 3 ps from model studies. The 2D IR spectra expose a significant distribution of nitrile frequencies that diffuse at equilibrium on ultrafast time scales ranging from hundreds of femtoseconds to tens of picoseconds. The slow spectral diffusion of the cyanovinyl arm of the inhibitor is attributed to its interaction with the backbone and side chains in the hydrophobic tunnel. The results show that the inhibitor cyano modes lose memory of their structural configurations relative to the hydrophobic pocket within tens of picoseconds. The cross-peaks between the two arms of the drug are tentatively attributed to relaxation of the nitrile state with both arms excited.