milerssliu/battery-device-data-qa huggingface dataset:
A button-sized hybrid electrolyte cell (Fig. S4†), in which an ionic liquid-infiltrated NCM with a LLZTO electrolyte and a 20 μm–thick Li metal were respectively used as a cathode and a Li metal anode, was fabricated to check out the improvement of the electrochemical performance after laser-annealing treatment. For comparison, two kinds of LLZTO pellets were used: a polished pellet without laser treatment and a laser-treated pellet. In Fig. 6a and b, the Nyquist plots of the AC-impedance spectra from the samples obtained at an open circuit from the cells were compared. As shown in Fig. 6a and b, the ohmic losses calculated from the high-frequency intercept with the real axis were almost the same in the range of 3.2–4.0 Ω cm2 for both the cells. Based on the ohmic resistance, the ionic conductivities were expected to be in the range of 7.5–9.4 10−3 S cm−1 at 60 °C for the LLZTO pellets with and without laser treatment. These conductivity values are consistent with the reported values of Ta-doped LLZO and also with that value (∼8.6 × 10−3 S cm−1 at 60 °C) experimentally obtained from the Au-sputtered symmetric cells (Au/LLZTO/Au), as shown in Fig. S5a.† Thus, it can be inferred that the cathode and ionic liquid catholyte are not contributing significantly to the ohmic losses in these cells. Furthermore, the amorphous layer formed by laser irradiation had no significant effect on the ohmic resistance due to its low thickness of about 400 nm. The AC-impedance spectra of both cells consist of a depressed arc in the high-frequency range, a narrow line inclined at a constant angle to the real axis (Warburg impedance), and a capacitive line (blocking region) in the low-frequency range, which are typical features of a NCM-Li cell. The high-frequency arc could be associated with the charge-transfer reactions at the cathode and anode interface. Because the relaxation times for the cathodic and anodic reactions are generally overlapped over the high-frequency ranges for a NCM-Li full cell, it is difficult to separate the charge-transfer resistance at the Li-LLZTO interface from the resistance at the NCM-ionic liquid. The AC-impedance spectrum for Li/LLZTO/Li cell is also shown in Fig. S5b.† Considering that the electrochemical kinetics at the cathode would be almost the same for both cells, the variation in the high-frequency arc could be attributed to the charge-transfer resistance at the Li metal and LLZTO interface. The values of the overall interfacial resistance, Rct, were quantitatively determined from complex non-linear least-square (CNLS) fitting of the measured impedance spectra based on a typical equivalent circuit of the NCM-Li full cell. The Rct (Rc + Ra) value was reduced from ∼80 Ω cm2 to ∼26 Ω cm2 when the LLZTO surface was treated by a laser beam. In addition, as shown in Fig. S5c,† the electronic conductivity of LLZTO was significantly reduced by the laser treatment, which can originate from the formation of a wide band gap surface layer.

Question: What's the anode?
Answer:  Li metal
A button-sized hybrid electrolyte cell (Fig. S4†), in which an ionic liquid-infiltrated NCM with a LLZTO electrolyte and a 20 μm–thick Li metal were respectively used as a cathode and a Li metal anode, was fabricated to check out the improvement of the electrochemical performance after laser-annealing treatment. For comparison, two kinds of LLZTO pellets were used: a polished pellet without laser treatment and a laser-treated pellet. In Fig. 6a and b, the Nyquist plots of the AC-impedance spectra from the samples obtained at an open circuit from the cells were compared. As shown in Fig. 6a and b, the ohmic losses calculated from the high-frequency intercept with the real axis were almost the same in the range of 3.2–4.0 Ω cm2 for both the cells. Based on the ohmic resistance, the ionic conductivities were expected to be in the range of 7.5–9.4 10−3 S cm−1 at 60 °C for the LLZTO pellets with and without laser treatment. These conductivity values are consistent with the reported values of Ta-doped LLZO and also with that value (∼8.6 × 10−3 S cm−1 at 60 °C) experimentally obtained from the Au-sputtered symmetric cells (Au/LLZTO/Au), as shown in Fig. S5a.† Thus, it can be inferred that the cathode and ionic liquid catholyte are not contributing significantly to the ohmic losses in these cells. Furthermore, the amorphous layer formed by laser irradiation had no significant effect on the ohmic resistance due to its low thickness of about 400 nm. The AC-impedance spectra of both cells consist of a depressed arc in the high-frequency range, a narrow line inclined at a constant angle to the real axis (Warburg impedance), and a capacitive line (blocking region) in the low-frequency range, which are typical features of a NCM-Li cell. The high-frequency arc could be associated with the charge-transfer reactions at the cathode and anode interface. Because the relaxation times for the cathodic and anodic reactions are generally overlapped over the high-frequency ranges for a NCM-Li full cell, it is difficult to separate the charge-transfer resistance at the Li-LLZTO interface from the resistance at the NCM-ionic liquid. The AC-impedance spectrum for Li/LLZTO/Li cell is also shown in Fig. S5b.† Considering that the electrochemical kinetics at the cathode would be almost the same for both cells, the variation in the high-frequency arc could be attributed to the charge-transfer resistance at the Li metal and LLZTO interface. The values of the overall interfacial resistance, Rct, were quantitatively determined from complex non-linear least-square (CNLS) fitting of the measured impedance spectra based on a typical equivalent circuit of the NCM-Li full cell. The Rct (Rc + Ra) value was reduced from ∼80 Ω cm2 to ∼26 Ω cm2 when the LLZTO surface was treated by a laser beam. In addition, as shown in Fig. S5c,† the electronic conductivity of LLZTO was significantly reduced by the laser treatment, which can originate from the formation of a wide band gap surface layer.

Question: What's the electrolyte?
Answer: LLZTO
A button-sized hybrid electrolyte cell (Fig. S4†), in which an ionic liquid-infiltrated NCM with a LLZTO electrolyte and a 20 μm–thick Li metal were respectively used as a cathode and a Li metal anode, was fabricated to check out the improvement of the electrochemical performance after laser-annealing treatment. For comparison, two kinds of LLZTO pellets were used: a polished pellet without laser treatment and a laser-treated pellet. In Fig. 6a and b, the Nyquist plots of the AC-impedance spectra from the samples obtained at an open circuit from the cells were compared. As shown in Fig. 6a and b, the ohmic losses calculated from the high-frequency intercept with the real axis were almost the same in the range of 3.2–4.0 Ω cm2 for both the cells. Based on the ohmic resistance, the ionic conductivities were expected to be in the range of 7.5–9.4 10−3 S cm−1 at 60 °C for the LLZTO pellets with and without laser treatment. These conductivity values are consistent with the reported values of Ta-doped LLZO and also with that value (∼8.6 × 10−3 S cm−1 at 60 °C) experimentally obtained from the Au-sputtered symmetric cells (Au/LLZTO/Au), as shown in Fig. S5a.† Thus, it can be inferred that the cathode and ionic liquid catholyte are not contributing significantly to the ohmic losses in these cells. Furthermore, the amorphous layer formed by laser irradiation had no significant effect on the ohmic resistance due to its low thickness of about 400 nm. The AC-impedance spectra of both cells consist of a depressed arc in the high-frequency range, a narrow line inclined at a constant angle to the real axis (Warburg impedance), and a capacitive line (blocking region) in the low-frequency range, which are typical features of a NCM-Li cell. The high-frequency arc could be associated with the charge-transfer reactions at the cathode and anode interface. Because the relaxation times for the cathodic and anodic reactions are generally overlapped over the high-frequency ranges for a NCM-Li full cell, it is difficult to separate the charge-transfer resistance at the Li-LLZTO interface from the resistance at the NCM-ionic liquid. The AC-impedance spectrum for Li/LLZTO/Li cell is also shown in Fig. S5b.† Considering that the electrochemical kinetics at the cathode would be almost the same for both cells, the variation in the high-frequency arc could be attributed to the charge-transfer resistance at the Li metal and LLZTO interface. The values of the overall interfacial resistance, Rct, were quantitatively determined from complex non-linear least-square (CNLS) fitting of the measured impedance spectra based on a typical equivalent circuit of the NCM-Li full cell. The Rct (Rc + Ra) value was reduced from ∼80 Ω cm2 to ∼26 Ω cm2 when the LLZTO surface was treated by a laser beam. In addition, as shown in Fig. S5c,† the electronic conductivity of LLZTO was significantly reduced by the laser treatment, which can originate from the formation of a wide band gap surface layer.

Question: What's the cathode?
Prior to its integration with the electrodes, various properties of the LLZO SE such as the microstructure, crystalline phase and ionic conductivity were characterized. To improve the Li ion conductivity in the parent LLZO structures, Nb5+ was doped at the Zr4+ sites to create Li+ vacancies, and Ba2+ was doped at the La3+ sites to increase the Li+ concentration.Fig. 1a shows the cross-sectional SEM image of the LLZO SE pellet. A dense microstructure was formed by the uniaxial pressing and the subsequent sintering steps. The relative density of the LLZO pellet was ∼95% which was the ratio of the theoretical density calculated using the lattice parameter derived from XRD and the real density measured using a He gas pycnometer. XRD analysis of the LLZO SE (Fig. 1b) reveals the cubic phase of LLZO, where most of the diffraction peaks relate to the parent Li–garnet phase “Li5La3Nb2O12” with the space group Iad. A small peak at ∼2θ = 30 degree corresponds to the presence of BaZrO3 impurities. LLZO exists in cubic and tetragonal polymorphs. The former is typically obtained at higher sintering temperatures (>1000 °C), and exhibits about two orders of magnitude higher Li-ion conduction.Fig. 1c shows the Nyquist plots of a Au|LLZO|Au quasi-blocking cell obtained at room temperature. Au metal was sputtered on either side of the LLZO pellet to obtain uniform contacts. The plots were fitted with a resistor–capacitor (constant phase element) circuit and a series capacitor. By fitting the high frequency (5–0.5 MHz) semi-circle, we obtain a capacitance of ∼2.7 × 10−10 F which could be attributed to the bulk and grain-boundary contributions to Li+ transport in the SE. In the low frequency range (<100 Hz), we observe a linear increase which reflects the quasi-blocking effect of the Au electrodes. From the low-frequency intercept of the semi-circle with the x-axis we determine a bulk resistance (RB) of ∼640 ± 1.4 Ω cm2. When using l as the thickness of the SE pellet and a as the electrode surface area, the ionic conductivity σ was calculated using the formula: σ = l/RBa, which was found to be ∼1.5 × 10−4 S cm−1. Further, σ is plotted as a function of increasing temperature T in Fig. 1d and the relationship follows an Arrhenius behavior as expressed by the following equation where σ is the conductivity of the electrolyte (S cm−1), A is the pre-exponential factor, T is the temperature (Kelvin), Ea is the activation energy expressed (eV), and kb is Boltzmann's constant. The activation energy Ea calculated from the Arrhenius plot is 0.35 eV, which is consistent with values reported in the literature. The EIS plots used to measure Ea are given in Fig. S1.†

Question: What's the electrolyte?
Bulk electrolysis was conducted to test the performance of CRLEs under conditions of electrochemical turnover. A series of charge/discharge experiments was performed for the negative and the positive electrolyte separately. The coulombic efficiency (CE) was calculated from photometric and coulometric data according to eqn (5), where npt are the number of moles obtained with photometry (c is the concentration, V is the volume, and 0.8 is the SoC difference), and nec the number of moles calculated from Faraday's law (I is the current, t is the time and F is the Faraday's constant).

Question: What's the electrolyte?