Synergistic multi-doping effects on the Li7La3Zr2O12 solid electrolyte for fast lithium ion conduction

Here, we investigate the doping effects on the lithium ion transport behavior in garnet Li(7)La(3)Zr(2)O(12) (LLZO) from the combined experimental and theoretical approach. The concentration of Li ion vacancy generated by the inclusion of aliovalent dopants such as Al(3+) plays a key role in stabilizing the cubic LLZO. However, it is found that the site preference of Al in 24d position hinders the three dimensionally connected Li ion movement when heavily doped according to the structural refinement and the DFT calculations. In this report, we demonstrate that the multi-doping using additional Ta dopants into the Al-doped LLZO shifts the most energetically favorable sites of Al in the crystal structure from 24d to 96 h Li site, thereby providing more open space for Li ion transport. As a result of these synergistic effects, the multi-doped LLZO shows about three times higher ionic conductivity of 6.14 × 10(−4) S cm(−1) than that of the singly-doped LLZO with a much less efforts in stabilizing cubic phases in the synthetic condition

Rechargeable Thin‐Film Lithium Microbattery Using a Quasi‐Solid‐State Polymer Electrolyte

International audienceAbstract A thin‐film microbattery was designed after synthesizing a unique gel polymer electrolyte (GPE), using polyvinylidene fluoride‐co‐hexafluoropropylene (PVdF‐HFP) and cross‐linked poly(ethylene oxide) (PEO), with an ionic liquid and salt (LiTFSI) mixture. The polymers resulted in a semi‐interpenetrated polymer network (semi‐IPN), hosting an ionic liquid (IL)/salt mixture, and thus exhibited high ionic conductivity and excellent mechanical properties. Nuclear magnetic resonance (NMR) diffusion measurements and relaxation rates analysis highlighted the existence of interactions between Li + ions and oxygen within the polymers, preventing electrolyte leakage and ensuring excellent mechanical strength which enabled a unique quasi‐solid electrolyte. Such mechanical strength and chemical stability made this electrolyte to be first ever reported GPE to withstand thermal evaporation deposition and hence direct deposition of lithium metal. The electrolyte could be shaped as self‐standing thin films, and thus worked as both separator and electrolyte in a thin‐film lithium microbattery. The thin‐film microbattery exhibited excellent performances showing no short‐circuit current, an open circuit voltage of ∼3.0 V, higher nominal voltage plateau, lower equivalent series resistance by comparison to a thin‐film microbattery designed in conventional way with a popular ceramic electrolyte LiPON

Glasses and glass-ceramics for solid-state battery applications- Chapter 50

International audienceThis chapter reviews investigations carried out in the last decades to synthesize and characterize ion conducting glasses and glass-ceramics and further use them as solid electrolytes in all-solid-state batteries.First, the focus is put on materials, either LiC, NaC or AgC conducting ones, with the most striking points being the discovery of ion conductingchalcogenide glasses in the 1980s, the elaboration of fast ion conducting glass-ceramics with the introduction of mechanical alloying techniques in the 1990s, and more recently the renewed interest in NaC conducting glasses and glass-ceramics.The second part of the chapter focuses on the development of all-solid-state batteries, Li-ion and Li=S batteries and to a lesser extent NaC and AgC-ion batteries. It is shown that the performance of the batteries relies on the development of optimized composite electrodes comprising theelectrolyte, an active material and a conductive additive. The review sheds light on the key parameters that have to be considered, including the choice of compositions of active material and conductive additive, coating of electrode by the electrolyte, coating of the electrolyte, ratio of thecomponents, homogenization of the mixture and compaction of the powders