Because of its stability, nanosized olivine LiFePO(4) opens the door toward high-power Li-ion battery technology for large-scale applications as required for plug-in hybrid vehicles. Here, we reveal that the thermodynamics of first-order phase transitions in nanoinsertion materials is distinctly different from bulk materials as demonstrated by the decreasing miscibility gap that appears to be strongly dependent on the overall composition in LiFePO(4). In contrast to our common thermodynamic knowledge, that dictates solubility limits to be independent of the overall composition, combined neutron and X-ray diffraction reveals strongly varying solubility limits below particle sizes of 35 nm. A rationale is found based on modeling of the diffuse interface. Size confinement of the lithium concentration gradient, which exists at the phase boundary, competes with the in bulk energetically favorable compositions. Consequently, temperature and size diagrams of nanomaterials require complete reconsideration, being strongly dependent on the overall composition. This is vital knowledge for the future nanoarchitecturing of superior energy storage devices as the performance will heavily depend on the disclosed nanoionic properties.

Li and Na metals have the highest theoretical anode capacity for Li/Na batteries, but the operational safety hazards stemming from uncontrolled growth of Li/Na dendrites and unstable electrode-electrolyte interfaces hinder their real-world applications. Recently, the emergence of 3D conductive scaffolds aimed at mitigating the dendritic growth to improve the cycling stability has gained traction. However, while achieving 3D scaffolds that are conducive to completely prevent dendritic Li/Na is challenging, the routes proposed to fabricate 3D scaffolds to date are often complex and expensive. This not only leads to suboptimal battery performance but can make the manufacturing nearly unachievable, compromising their commercial viability. We herein introduce a facile and single-step route to honeycomb-like 3D porous Ni@Cu scaffolds via a hydrogen bubble dynamic template (HBDT) electrodeposition method. The current collectors fabricated by this method offer highly stable cycling performance of Li plating/stripping (> 300 cycles at 0.5 mAh cm-2 and over 200 cycles at 1.0 mAh cm-2), attributed to their ability to effectively accommodate Li/Na deposits in their porous networks and to delocalize the charge distribution. The beneficial role of LiNO3 as an electrolyte additive in improving the mechanical integrity of solid electrolyte interface (SEI) and mechanistic insights into how the 3D porous structure facilitates Li/Na plating/stripping are comprehensively presented. Finally, with an outstanding cycling performance of reversible Na deposition (over 240, 110 and 50 cycles for 0.5, 1.0 and 2.0 mAh cm-2 at 1.0 mA cm-2), our findings open new doors to expedite the development of Li/Na metal battery technology.

In common hybrid solid electrolytes (HSEs), either the ionic conductivity of the polymer electrolyte is enhanced by the presence of a nanosized inorganic filler, which effectively decrease the glass-transition temperature, or the polymer solid electrolyte acts mostly as a flexible host for the inorganic solid electrolyte, the latter providing the conductivity. Here a true HSE is developed that makes optimal use of the high conductivity of the inorganic solid electrolyte and the flexibility of the polymer matrix. It is demonstrated that the LAGP (Li1.5Al0.5Ge1.5(PO4)3) participates in the overall conductivity and that the interface environment between the poly­(ethylene oxide) (PEO) and LAGP plays a key role in utilizing the high conductivity of the LAGP. This HSE demonstrates promising cycling versus Li-metal anodes and in a full Li-metal solid-state battery. This strategy offers a promising route for the development of Li-metal solid-state batteries, aiming for safe and reversible high-energy-density batteries.

Future applications of discotic liquid crystals (DLCs) in electronic devices depend on a marked improvement of their conductivity properties. We present a study of 2,3,6,7,10,11-hexakishexyloxytriphenylene (HAT6) and show how local conformation, structural defects, and thermal motions on the picosecond time scale strongly affect the efficient charge transport in DLCs. A direct and successful comparison of classical molecular dynamics (MD) simulations with both neutron powder diffraction and quasielastic neutron scattering (QENS) give a full insight into the structural and dynamical properties of HAT6. The local conformation of HAT6 molecules is characterized by a mutual rotation (twist) angle of about 37° and typically a mutual aromatic-core distance of 3.4 Å instead of the average distance of 3.65 Å usually quoted. We show that a considerable number of structural traps is present in HAT6, which persist at the picosecond time scale. We find that the high disorder in the mutual positions of the aromatic cores is an important factor contributing to the limited conductivity of HAT6 compared to larger DLCs.

Solid-state lithium-metal batteries are considered to be promising candidates for next-generation high-energy density storage devices to power electrical vehicles. Critical challenges for solid-state lithium-metal batteries include the large morphological changes associated with the plating and stripping of lithium metal and decomposition of the solid electrolyte, because of the reductive nature of the lithium metal, both increasing the lithium metal−solid electrolyte interface resistance. This is especially challenging when starting in the discharged state with a bare anode or "anode-less" current collector facing the solid electrolyte. To overcome this, a 100nm thin layer of ZnO is deposited on the copper current collector with atomic layer deposition (ALD). During the first charge, this results in more homogeneous lithium-metal growth, rationalized by the formation of a Zn−Li alloy that acts as seed crystals for the lithium metal. The resulting more homogeneous lithium-metal growth maintains better contact with the solid electrolyte, leading to more reversible cycling of lithium metal. Minor prelithiating of the ZnO/Cu anode with 1 mAh/ cm 2 further improves the cycling performance, as demonstrated in a full all-solid-state cell using LiFePO 4 as a cathode, resulting in an average Coulombic efficiency of >95%. These findings mark the first steps in an interface strategy to overcome the challenges at the solid electrolyte/lithium-metal interface in solid-state lithium-metal batteries.