Li-containing garnet materials have been attracting considerable
interest as potential solid-state electrolytes for Li ion batteries.
In such Ln3M2Li
x
O12 (Ln = lanthanide, alkaline earth; M = Zr, Hf, Sn,
Nb, Ta, Sb, Bi, Te), the best Li ion conductivity is observed for
Li contents, x, just below the maximum 7.0. The decrease
in conductivity for x = 7.0 systems is related to
Li ordering (cell changes from cubic to tetragonal) to prevent too
short Li–Li interactions. In this work, we report a combined
experimental and modeling study of Ce4+ doping in La3Zr2Li7O12. We show for the
first time that Ce4+ can be doped onto the Zr4+ site in this material. This doping strategy results in a reduction
in the tetragonal distortion as well as a lowering of the temperature
of the tetragonal–cubic phase transition, attributed to the
increase in cell size reducing Li–Li interaction strain. Coupled
with these changes, the conductivity shows a significant (1.5 orders
of magnitude) improvement. Furthermore, the Ce doping also reduces
the interfacial resistance (388 Ω cm2 for Li7La3Z1.75Ce0.25O12) in contact with Li metal, giving additional potential
benefits to this doping strategy. The long-term cycling stability
of a Li//garnet//Li symmetric cell over 190 h has been demonstrated.
Where a licence is displayed above, please note the terms and conditions of the licence govern your use of this document. When citing, please reference the published version. Take down policy While the University of Birmingham exercises care and attention in making items available there are rare occasions when an item has been uploaded in error or has been deemed to be commercially or otherwise sensitive.
Solid-state batteries are a proposed route to safely achieving high energy densities, yet this architecture faces challenges arising from interfacial issues between the electrode and solid electrolyte. Here we develop a novel family of double perovskites, Li1.5La1.5MO6 (M = W6+, Te6+), where an uncommon lithium-ion distribution enables macroscopic ion diffusion and tailored design of the composition allows us to switch functionality to either a negative electrode or a solid electrolyte. Introduction of tungsten allows reversible lithium-ion intercalation below 1 V, enabling application as an anode (initial specific capacity >200 mAh g-1 with remarkably low volume change of ∼0.2%). By contrast, substitution of tungsten with tellurium induces redox stability, directing the functionality of the perovskite towards a solid-state electrolyte with electrochemical stability up to 5 V and a low activation energy barrier (<0.2 eV) for microscopic lithium-ion diffusion. Characterisation across multiple length- and time-scales allows interrogation of the structure-property relationships in these materials and preliminary examination of a solid-state cell employing both compositions suggests lattice-matching avenues show promise for all-solid-state batteries.
The electronic structure properties of four related push–pull systems are studied using time-dependent density functional theory in connection with detailed wavefunction analysis protocols.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.