PDF Publication Title:
Text from PDF Page: 014
Reviews Table 1 | types of interfaces between li metal and solid electrolytes containing different cations anion X stable against li metal sei formers MCi formers O Be2+, Ca2+, Sc3+, Y3+, Hf4+, lanthanide series (La3+)a (refs155,182) H+, N5+, P5+, Sx+, Sex+, Tex+, Clx+, Brx+, Ix+ (P5+)73 Others: Fe3+ (ref.156), Zr4+,b (ref.155), Nb5+ (ref.155), Ti4+ (refs63,198), Ge4+ (ref.198) S Ca2+, Sr2+, Ba2+, lanthanide seriesc Same as O chemistry (H+)d (ref.114), P5+ (ref.52) Others: Ge4+ (refs52,111), Sn4+ (ref.111), Si4+ (ref.111), Sb4+,d (ref.114) Cl K+, Rb+, Cs+, Sr2+, Ba2+, Yb2+ Same as O chemistry Others Br Na+, K+, Rb+, Cs+, Sr2+, Ba2+, Yb2+ Same as O chemistry Others N Be2+, Mg2+, Ca2+, Sr2+, Sc3+, Y3+, Re3+, B3+, Al3+, C4+, Si4+, Ti4+, Zr4+, Hf4+, V5+, Nb5+, Ta5+, Mn5+, Cr6+, Mo6+, W6+, lanthanide series Same as O chemistry Others The classification is based on the computed Li–M–X phase diagrams as an approximation224. If there is a M–X or Li–M–X compound that is stable against Li, the M cation is classified as stable against Li. If no such stable binary or ternary phase exists, the interphase is classified as a former of a solid electrolyte interphase (SEI, if the Li-stable phases are electron insulators) or, otherwise, of a mixed ionic–electronic conducting interphase (MCI). The cations in parentheses have been experimentally confirmed and only cations with elements in the first six periods in the periodic table are considered. Computational data from refs224,233 and the Materials Project83. M, non-Li cation; X, anion. aAl3+ and Ta5+ are also observed to be stable against Li metal in experiments152,155,198, although they are predicted to be reduced below 0.06 V for Al3+ in Li5AlO4 and 0.35 V for Ta5+ in Li5TaO5. bStill in debate in experiments. Although the reduction of Zr4+ by Li metal was observed in X-ray photoelectron spectroscopy97,154,155, apparent stability or passivation between Li metal and Zr4+-containing solid electrolytes has been reported149–151,155,205,206. cExcluding Dy2+, Ho2+, Er2+, Tm2+ and Lu2+ for the sulfide chemistry. dObserved in Na solid-state batteries. LiInO2 (ref.217) and Li2MoO4 (ref.218). However, the dif- fusion of Co from LiCoO2 into the oxide coating layer has been observed upon extended cycling104, leading to the gradual deterioration of the coating in the long term. Although garnets are less reactive than sulfides, the reac- tivity between the garnet and the oxide cathode during high-temperature co-sintering cannot be neglected, as we discussed. Glassy Li3BO3 with a melting temperature of approximately 700 °C has often been used as a buffer layer to stabilize garnet/cathode interfaces54,128,219. The good performance of currently used coating materials can be explained by their wide electrochemical stability window up to ~4 V (ref.165) and reduced reactiv- ity with the oxide cathode and SE64,65. However, most of these materials cannot withstand the Li-extraction poten- tial of high-voltage cathodes. For LiNbO3 and LiTaO3 coatings, a non-trivial driving force (>100 meV/atom) for chemical mixing still exists between the coating and sulfide SEs65,67. A recent high-throughput computa- tional screening considered the electrochemical stability, chemical stability and ionic conductivity of Li-containing materials67. Polyanionic oxides with non-metal–oxygen bonds were shown to be promising cathode coatings, with appealing examples including LiH2PO4, NASICON LiTi2(PO4)3 and LiPO3. To illustrate the function of poly- anionic compounds as a buffer layer between an oxide cathode and a sulfide SE, fig. 5a shows the reaction energies of representative (non-polyanionic) oxide and polyanionic oxide coatings with common cathodes and SEs67. The oxide cathode/sulfide SE interface suffers from a strong driving force for anion exchange between O2− and S2− to form P–O bonds. In addition, the forma- tion of Li3PO4 is highly favourable because of its deep formation energy (−2.767 eV/atom), which destabi- lizes oxide cathodes or oxide coating materials in con- tact with Li-rich sulfide conductors. By contrast, many polyanionic coatings (such as phosphates and borates) exhibit improved chemical stability with both the oxide cathode and sulfide SE, as indicated by the dark green colour in the corresponding cells in fig. 5a. There are two reasons for this stability: (1) the strong orbital hybridiza- tion between non-metal and oxygen in the polyanionic group creates strong covalent bonds (such as P–O and B–O), which are chemically inert against reaction and (2) polyanionic oxides such as the phosphates share the same anion (O2−) with oxides and the same cation (P5+) with thio-phosphates, thereby removing the energy gain from anion exchange. The compatibility issues among the polyanionic oxide, oxide and sulfide chemistries are summarized in fig. 5b. It should be noted that the ten- dency to form the stable Li3PO4 phase still exists when phosphates contact a Li source67. Electrochemically, hybridization in polyanionic oxides also lowers the oxy- gen electron states, boosting the oxidation stability67. Indeed, very recently, the NASICON Li1.5Al0.5Ti1.5(PO4)3 was employed as a catholyte between LiNi0.8Co0.1Mn0.1O2 and a β-Li3PS4 SE layer in a full cell129. The capacity reten- tion was improved compared with directly using β-Li3PS4 as the catholyte and the decomposition at the SE/cathode interface was suppressed. Anode coatings On the anode side, several classes of compounds, includ- ing oxides, polyanionic oxides and nitrides, have been used to stabilize the SE/Li interface. Compounds in the Li–Al–O chemical space have provided effective protec- tion for various SEs against Li metal, including Li7P3S11, LATP and Li7La2.75Ca0.25Zr1.75Nb0.25O12 (refs62,220,221). The computedstabilitywindowofLi5AlO4 is0.06–3.07V, suggesting good stability of Al3+ against Li metal, which is also consistent with XPS observations at the LAGP/Li interface198. In addition, in situ-formed polyanionic com- pounds Li3PO4 and LiH2PO4 have been used to stabilize the LLZO/Li and LGPS/Li interfaces, respectively222,223. DFT predicted that Li3PO4 would form Li3P and Li2O in contact with Li metal, as well as LiH for LiH2PO4. These reaction products are passivating and can enable the stable cycling of Li symmetric cells, similar to the www.nature.com/natrevmatsPDF Image | Understanding interface stability in solid-state batteries
PDF Search Title:
Understanding interface stability in solid-state batteriesOriginal File Name Searched:
2019_xiao_nature_review.pdfDIY PDF Search: Google It | Yahoo | Bing
Sulfur Deposition on Carbon Nanofibers using Supercritical CO2 Sulfur Deposition on Carbon Nanofibers using Supercritical CO2. Gamma sulfur also known as mother of pearl sulfur and nacreous sulfur... More Info
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)