Lithium ion dynamics in LiZr₂(PO₄)₃ and Li_1.4Ca_0.2Zr_1.8(PO₄)₃

Abstract

7Li NMR reveals rapid cation exchange processes in NASICON-type Li1.4Ca0.2Zr1.8(PO4)3 on a local length scale.

Methods for Lithium Ion NASICON Preparation: From Solid-State Synthesis to Highly Conductive Glass-Ceramics

“…These studies were determinant to establish the influence of the composition in the conductivity of electrolytes. A summary of the most important results for lithium-containing NASICONs synthesized by this method is summarized in Table . − ,− ,,,,,,− The parameters E a and σ are presented, in which E a is the total activation energy and σ is the conductivity at room temperature (considered between 15 and 30 °C). The method for shaping and the sintering conditions are also described.…”

Free-Standing, Robust, and Stable Li+ Conductive Li(Sr,Zr)2(PO4)3/PEO Composite Electrolytes for Solid-State Batteries

“…Rietveld refine-ment of the LZP compound was also conducted using diffraction data, and the obtained patterns of Sr-doped samples are shown in Figure S1. Since LZP generally has two main polymorphs, either a low-temperature phase (OR and MN) or a high-temperature phase (RH), 8,9 we obtain the slightly higher profile R-factors, where R wp were 10.69 and 13.25% for LZP and LSZP, respectively, which raises a question on the purity of the given compounds. Nevertheless, we can realize that Sr doping does not distort the LZP RH structure and the resultant composite electrolytes have relatively high Li conductivity subsequent σ-temperature data.…”

“…Even with the substitutional Sr 2+ and excess Li + ions, the overall diffraction peaks matched well with LiZr 2 (PO 4 ) 3 (JCPDS 070-6734). 8,9 We realize that the given compounds are proper Li + conductors, while the higher index planes with a low diffraction intensity, peaks positioned above 2θ = 40°, are slightly overlapped, indicating unsettled phase purity. Rietveld refine-ment of the LZP compound was also conducted using diffraction data, and the obtained patterns of Sr-doped samples are shown in Figure S1.…”

“…Nowadays, lithium-ion conducting solid-state electrolyte systems include Na superionic conductor (NASICON)-type phosphate, polymer, oxide, and sulfide compounds. Compared with other electrolyte systems, the NASICON-type system exhibits enough ionic conductivity with a high-enough transference number to fulfill the requirements of all-solid-state LIBs. − The NASICON-type LiMe 2 (PO 4 ) 3 (Me = Zr, Ti, and Ge) phosphates have a three-dimensional framework favorable to the mobile Li + ions during electrochemical reactions. The standard methods for preparing the phosphates include solid-state reactions, sol–gel synthesis, co-precipitation, quenching, and so forth, which result in comparable Li + conductivity with better thermal/mechanical stability. − Nevertheless, the challenges faced by the NASICON-type electrolytes include harsh process conditions and extremely high interfacial resistances with the electrodes, which block the large-scale production and low energy conversion efficiency in all-solid-state lithium batteries (ASSLBs).…”

Combining Deformation, Heat, and Ionic Conductivity to Improve the Electrochemical Performance and Safety of Li-Ion Batteries under Extreme Conditions

“…As a NTE material with high Li-ion conductivity, the thermal expansion coefficient of LiZr 2 (PO 4 ) 3 is −4.0 × 10 –6 /°C during the temperature range from −200 to 500 °C. − Furthermore, LiZr 2 (PO 4 ) 3 is stable between 0 and 5.5 V, , which covers the working voltage ranges of general LIBs. The triclinic structure (α′-LiZr 2 (PO 4 ) 3 ) obtained at about 900 °C exhibits lower ionic conductivity (∼10 –8 S/cm), and the highly conductive (∼10 –5 S/cm) rhombohedral structure (α-LiZr 2 (PO 4 ) 3 ) is formed at 1200 °C . In addition, the phase of α′-LiZr 2 (PO 4 ) 3 will transform to α-LiZr 2 (PO 4 ) 3 above 50 °C, which means that LiZr 2 (PO 4 ) 3 displays a higher ionic conductivity at increased temperatures …”