milerssliu/battery-device-data-qa huggingface dataset:
Using density functional theory (DFT), we calculated the free energy of hydrogen (ΔGH) on various coating materials as well as their electronic conductivity, and used these two parameters to screen for the best candidate material. Materials with suitable hydrogen adsorption (neither too strong nor too weak) located at the top of volcano plots would have optimum activity. Hence, materials with either very strong (highly negative −ΔGH) or very weak bonding (highly positive +ΔGH) should be ideal candidates to suppress the HER. The high ΔGH of Al2O3 (Fig. 1b) suggested its suitability whereas TiO2, despite its high ΔGH, became highly catalytic towards the HER once lithiated into LiTi2O4 (as characterized by a low ΔGH). This increased catalytic activity according to the degree of lithiation might explain why LTO in non-aqueous batteries effectively catalyzed the decomposition of trace H2O present in electrodes and electrolyte. With a highly negative ΔGH, ZnO would also serve as a good candidate for HER suppression. However, its high electronic conductivity accelerated the charge transfer between the electrolyte and electrodes, which kinetically favors the electrochemical reduction of water. Conversely, Al2O3 had a large bandgap (5.33 eV) (Fig. 1c), which suggested very poor electrical conductivity that prevented charge transfer, in sharp comparison with the bandgaps of lithiated LiTi2O4 (0 eV) and ZnO (1.48 eV), respectively. In fact, the latter two were well known for their metallic and semiconducting behaviors (Fig. 1d and S1†). Therefore, the insulator Al2O3 would be the best candidate surface for HER suppression.

Question: What's the electrolyte?
To facilitate the practical realization of sodium-ion batteries, the energy density, determined by the output operating voltage and/or capacity, needs to be improved to the level of commercial Li-ion batteries. Herein, O3-type Na0.98Ca0.01[Ni0.5Mn0.5]O2 is synthesized by incorporating Ca2+ into the NaO6 octahedron of Na[Ni0.5Mn0.5]O2 and its potential use as a cathode material for high energy density SIBs is demonstrated. The ionic radius of calcium (≈1.00 Å) is similar to that of sodium (≈1.02 Å); hence, it is energetically favorable for calcium to occupy sites in the sodium layers. Within a wide operating voltage range of 2.0–4.3 V, O3-type Na0.98Ca0.01[Ni0.5Mn0.5]O2 exhibits a reversible O3–P3–O3 phase transition with small volume changes compared to Ca-free Na[Ni0.5Mn0.5]O2 because of the strong interaction between Ca2+ and O2− and delivers a high reversible capacity of 209 mA h g−1 at 15 mA g−1 with improved cycling stability. Moreover, Ca substitution improves the practically useful aspects such as thermal and air stability. A prototype pouch full cell with a hard carbon anode shows an excellent capacity retention of 67% over 300 cycles. Thus, this study provides an efficient and simple method to boost the performance and applicability of layered oxide cathode materials for practical applications.

Question: What's the cathode?
Answer: Na[Ni0.5Mn0.5]O2
To facilitate the practical realization of sodium-ion batteries, the energy density, determined by the output operating voltage and/or capacity, needs to be improved to the level of commercial Li-ion batteries. Herein, O3-type Na0.98Ca0.01[Ni0.5Mn0.5]O2 is synthesized by incorporating Ca2+ into the NaO6 octahedron of Na[Ni0.5Mn0.5]O2 and its potential use as a cathode material for high energy density SIBs is demonstrated. The ionic radius of calcium (≈1.00 Å) is similar to that of sodium (≈1.02 Å); hence, it is energetically favorable for calcium to occupy sites in the sodium layers. Within a wide operating voltage range of 2.0–4.3 V, O3-type Na0.98Ca0.01[Ni0.5Mn0.5]O2 exhibits a reversible O3–P3–O3 phase transition with small volume changes compared to Ca-free Na[Ni0.5Mn0.5]O2 because of the strong interaction between Ca2+ and O2− and delivers a high reversible capacity of 209 mA h g−1 at 15 mA g−1 with improved cycling stability. Moreover, Ca substitution improves the practically useful aspects such as thermal and air stability. A prototype pouch full cell with a hard carbon anode shows an excellent capacity retention of 67% over 300 cycles. Thus, this study provides an efficient and simple method to boost the performance and applicability of layered oxide cathode materials for practical applications.

Question: What's the anode?
Answer: hard carbon
To facilitate the practical realization of sodium-ion batteries, the energy density, determined by the output operating voltage and/or capacity, needs to be improved to the level of commercial Li-ion batteries. Herein, O3-type Na0.98Ca0.01[Ni0.5Mn0.5]O2 is synthesized by incorporating Ca2+ into the NaO6 octahedron of Na[Ni0.5Mn0.5]O2 and its potential use as a cathode material for high energy density SIBs is demonstrated. The ionic radius of calcium (≈1.00 Å) is similar to that of sodium (≈1.02 Å); hence, it is energetically favorable for calcium to occupy sites in the sodium layers. Within a wide operating voltage range of 2.0–4.3 V, O3-type Na0.98Ca0.01[Ni0.5Mn0.5]O2 exhibits a reversible O3–P3–O3 phase transition with small volume changes compared to Ca-free Na[Ni0.5Mn0.5]O2 because of the strong interaction between Ca2+ and O2− and delivers a high reversible capacity of 209 mA h g−1 at 15 mA g−1 with improved cycling stability. Moreover, Ca substitution improves the practically useful aspects such as thermal and air stability. A prototype pouch full cell with a hard carbon anode shows an excellent capacity retention of 67% over 300 cycles. Thus, this study provides an efficient and simple method to boost the performance and applicability of layered oxide cathode materials for practical applications.

Question: What's the electrolyte?
To overcome this limitation, analysis of Differential Capacity Plots (DCPs) has been performed to identify electrochemical charge/discharge reactions and track their evolution during cycling. Fig. 6 shows the DCPs for the different Si/Ni–Sn/Al/C composites at cycles 2, 80 and 200 corresponding to composite activation, maximum capacity and end-of-cycling states. For Si-B, at the 2nd lithiation (Fig. 6a), three reduction peaks are observed in the cathodic branch. The peak at 0.17 V is attributed to the reaction potential of amorphous Si with lithium to form LixSi alloys of approximate composition LiSi and Li7Si3. Silicon amorphisation is known to occur during the first lithiation of crystalline Si anodes. The two other reduction peaks at 0.31 and 0.62 V are attributed to the formation of LiySn alloys: Li7Sn2 and LiSn, respectively. On delithiation, multiple oxidation peaks are detected and are attributed to the decomposition of Li7Si3 at 0.51 V and different LiySn alloys: Li7Sn2 (or Li22Sn5), Li5Sn2, LiSn and Li2Sn5 at 0.47, 0.58, 0.74 and 0.81 V, respectively. The two phases Li7Sn3 and Li13Sn5 have compositions close to Li5Sn2 and could be involved in the delithiation process at 0.58 V. For both composites Si-AB and Si-A, poorly defined cathodic peaks are found at the 2nd lithiation, but DCPs exhibit significant features in delithiation. For Si-AB, two oxidation peaks are clearly identified at 0.47 and 0.58 V attributed to the decomposition of Li7Sn2 (or Li22Sn5) and Li5Sn2 alloys, respectively. For Si-A, a unique broad oxidation peak is observed at 0.51 V assigned to the decomposition of Li7Si3. Interestingly, no signal related to the decomposition of LiySn alloys is detected for the composite Si-A, suggesting that Ni3Sn2 does not react with lithium.

Question: What's the anode?
Answer: Si
To overcome this limitation, analysis of Differential Capacity Plots (DCPs) has been performed to identify electrochemical charge/discharge reactions and track their evolution during cycling. Fig. 6 shows the DCPs for the different Si/Ni–Sn/Al/C composites at cycles 2, 80 and 200 corresponding to composite activation, maximum capacity and end-of-cycling states. For Si-B, at the 2nd lithiation (Fig. 6a), three reduction peaks are observed in the cathodic branch. The peak at 0.17 V is attributed to the reaction potential of amorphous Si with lithium to form LixSi alloys of approximate composition LiSi and Li7Si3. Silicon amorphisation is known to occur during the first lithiation of crystalline Si anodes. The two other reduction peaks at 0.31 and 0.62 V are attributed to the formation of LiySn alloys: Li7Sn2 and LiSn, respectively. On delithiation, multiple oxidation peaks are detected and are attributed to the decomposition of Li7Si3 at 0.51 V and different LiySn alloys: Li7Sn2 (or Li22Sn5), Li5Sn2, LiSn and Li2Sn5 at 0.47, 0.58, 0.74 and 0.81 V, respectively. The two phases Li7Sn3 and Li13Sn5 have compositions close to Li5Sn2 and could be involved in the delithiation process at 0.58 V. For both composites Si-AB and Si-A, poorly defined cathodic peaks are found at the 2nd lithiation, but DCPs exhibit significant features in delithiation. For Si-AB, two oxidation peaks are clearly identified at 0.47 and 0.58 V attributed to the decomposition of Li7Sn2 (or Li22Sn5) and Li5Sn2 alloys, respectively. For Si-A, a unique broad oxidation peak is observed at 0.51 V assigned to the decomposition of Li7Si3. Interestingly, no signal related to the decomposition of LiySn alloys is detected for the composite Si-A, suggesting that Ni3Sn2 does not react with lithium.

Question: What's the electrolyte?
A sodium-based analog of 3a, i.e. sodium rhodizonate 3b, was tested by Goodenough et al. with an anode based on a liquid sodium–potassium alloy (NaK). The advantage of this anode is its dendrite-free nature, making it safer compared to pristine potassium. In a DME-based KFSI solution, Qm was ∼120 mA h g−1 at 125 mA g−1, with ∼50 mA h g−1 delivered at 1.25 A g−1. The capacity retention was ca. 75% after 100 cycles.

Question: What's the anode?
A sodium-based analog of 3a, i.e. sodium rhodizonate 3b, was tested by Goodenough et al. with an anode based on a liquid sodium–potassium alloy (NaK). The advantage of this anode is its dendrite-free nature, making it safer compared to pristine potassium. In a DME-based KFSI solution, Qm was ∼120 mA h g−1 at 125 mA g−1, with ∼50 mA h g−1 delivered at 1.25 A g−1. The capacity retention was ca. 75% after 100 cycles.

Question: What's the electrolyte?
The Zn symmetric and Zn–Ti asymmetric cells were assembled as CR2030 coin cells to measure the electrochemical performances. Glass fiber and a 3 M Zn(CF3SO3)2 aqueous solution were used as the separator and the electrolyte, respectively. Before cell fabrication, Ti foil, bare Zn foil and PAM/PVP-coated Zn were cut into disk-shaped electrodes. The symmetric cells consist of two bare Zn foils (or PAM/PVP-coated Zn foils) separated by a glass fiber separator. The cells underwent galvanostatic charge and discharge cycling at a current density of 0.2–10 mA cm−2 on a Neware battery testing instrument. These experiments were performed to evaluate the stripping/plating behavior and cycling stability of the bare Zn and PAM/PVP-coated Zn anodes. Furthermore, Zn–Ti asymmetric cells were fabricated to investigate the coulombic efficiency of Zn stripping/plating. The asymmetric cell was initially discharged for 10 min, and then to 2.0 V at various current densities from 0.2–20 mA cm−2. To obtain the corrosion potential (Ecorr) and corrosion current density (Icorr), Tafel plots of the Zn symmetric cells were recorded on an electrochemical workstation (CHI660E, China) at a scan rate of 10 mV s−1. Chronoamperograms (CAs) of the bare Zn and the PAM/PVP-coated Zn symmetric cells were recorded under a −200 mV overpotential. The Zn–AC hybrid supercapacitors were fabricated with AC as the cathode, bare Zn or PAM/PVP-coated Zn foil as the anode, and 3 M Zn(CF3SO3)2 aqueous solution as the electrolyte. The cathode slurry was fabricated by mixing the cathode active materials, Super P, and PTFE at a mass ratio of 80:10:10. The resulting slurry was rolled into a thin film with a thickness of about 120 μm. Finally, the film was cut into discs with a diameter of 10 mm, pressed into a Ti mesh (15 mm in diameter) and dried in a vacuum oven at 100 °C for 6 h. The electrochemical performance was evaluated by cyclic voltammetry on an electrochemical workstation. The galvanostatic charge–discharge processes of the Zn–AC hybrid supercapacitor were recorded on a Neware battery testing system.

Question: What's the cathode?
Answer: AC
The Zn symmetric and Zn–Ti asymmetric cells were assembled as CR2030 coin cells to measure the electrochemical performances. Glass fiber and a 3 M Zn(CF3SO3)2 aqueous solution were used as the separator and the electrolyte, respectively. Before cell fabrication, Ti foil, bare Zn foil and PAM/PVP-coated Zn were cut into disk-shaped electrodes. The symmetric cells consist of two bare Zn foils (or PAM/PVP-coated Zn foils) separated by a glass fiber separator. The cells underwent galvanostatic charge and discharge cycling at a current density of 0.2–10 mA cm−2 on a Neware battery testing instrument. These experiments were performed to evaluate the stripping/plating behavior and cycling stability of the bare Zn and PAM/PVP-coated Zn anodes. Furthermore, Zn–Ti asymmetric cells were fabricated to investigate the coulombic efficiency of Zn stripping/plating. The asymmetric cell was initially discharged for 10 min, and then to 2.0 V at various current densities from 0.2–20 mA cm−2. To obtain the corrosion potential (Ecorr) and corrosion current density (Icorr), Tafel plots of the Zn symmetric cells were recorded on an electrochemical workstation (CHI660E, China) at a scan rate of 10 mV s−1. Chronoamperograms (CAs) of the bare Zn and the PAM/PVP-coated Zn symmetric cells were recorded under a −200 mV overpotential. The Zn–AC hybrid supercapacitors were fabricated with AC as the cathode, bare Zn or PAM/PVP-coated Zn foil as the anode, and 3 M Zn(CF3SO3)2 aqueous solution as the electrolyte. The cathode slurry was fabricated by mixing the cathode active materials, Super P, and PTFE at a mass ratio of 80:10:10. The resulting slurry was rolled into a thin film with a thickness of about 120 μm. Finally, the film was cut into discs with a diameter of 10 mm, pressed into a Ti mesh (15 mm in diameter) and dried in a vacuum oven at 100 °C for 6 h. The electrochemical performance was evaluated by cyclic voltammetry on an electrochemical workstation. The galvanostatic charge–discharge processes of the Zn–AC hybrid supercapacitor were recorded on a Neware battery testing system.

Question: What's the anode?
Answer: the bare Zn and PAM/PVP-coated Zn
The Zn symmetric and Zn–Ti asymmetric cells were assembled as CR2030 coin cells to measure the electrochemical performances. Glass fiber and a 3 M Zn(CF3SO3)2 aqueous solution were used as the separator and the electrolyte, respectively. Before cell fabrication, Ti foil, bare Zn foil and PAM/PVP-coated Zn were cut into disk-shaped electrodes. The symmetric cells consist of two bare Zn foils (or PAM/PVP-coated Zn foils) separated by a glass fiber separator. The cells underwent galvanostatic charge and discharge cycling at a current density of 0.2–10 mA cm−2 on a Neware battery testing instrument. These experiments were performed to evaluate the stripping/plating behavior and cycling stability of the bare Zn and PAM/PVP-coated Zn anodes. Furthermore, Zn–Ti asymmetric cells were fabricated to investigate the coulombic efficiency of Zn stripping/plating. The asymmetric cell was initially discharged for 10 min, and then to 2.0 V at various current densities from 0.2–20 mA cm−2. To obtain the corrosion potential (Ecorr) and corrosion current density (Icorr), Tafel plots of the Zn symmetric cells were recorded on an electrochemical workstation (CHI660E, China) at a scan rate of 10 mV s−1. Chronoamperograms (CAs) of the bare Zn and the PAM/PVP-coated Zn symmetric cells were recorded under a −200 mV overpotential. The Zn–AC hybrid supercapacitors were fabricated with AC as the cathode, bare Zn or PAM/PVP-coated Zn foil as the anode, and 3 M Zn(CF3SO3)2 aqueous solution as the electrolyte. The cathode slurry was fabricated by mixing the cathode active materials, Super P, and PTFE at a mass ratio of 80:10:10. The resulting slurry was rolled into a thin film with a thickness of about 120 μm. Finally, the film was cut into discs with a diameter of 10 mm, pressed into a Ti mesh (15 mm in diameter) and dried in a vacuum oven at 100 °C for 6 h. The electrochemical performance was evaluated by cyclic voltammetry on an electrochemical workstation. The galvanostatic charge–discharge processes of the Zn–AC hybrid supercapacitor were recorded on a Neware battery testing system.

Question: What's the electrolyte?
Answer: 3 M Zn(CF3SO3)2 aqueous solution
The Zn symmetric and Zn–Ti asymmetric cells were assembled as CR2030 coin cells to measure the electrochemical performances. Glass fiber and a 3 M Zn(CF3SO3)2 aqueous solution were used as the separator and the electrolyte, respectively. Before cell fabrication, Ti foil, bare Zn foil and PAM/PVP-coated Zn were cut into disk-shaped electrodes. The symmetric cells consist of two bare Zn foils (or PAM/PVP-coated Zn foils) separated by a glass fiber separator. The cells underwent galvanostatic charge and discharge cycling at a current density of 0.2–10 mA cm−2 on a Neware battery testing instrument. These experiments were performed to evaluate the stripping/plating behavior and cycling stability of the bare Zn and PAM/PVP-coated Zn anodes. Furthermore, Zn–Ti asymmetric cells were fabricated to investigate the coulombic efficiency of Zn stripping/plating. The asymmetric cell was initially discharged for 10 min, and then to 2.0 V at various current densities from 0.2–20 mA cm−2. To obtain the corrosion potential (Ecorr) and corrosion current density (Icorr), Tafel plots of the Zn symmetric cells were recorded on an electrochemical workstation (CHI660E, China) at a scan rate of 10 mV s−1. Chronoamperograms (CAs) of the bare Zn and the PAM/PVP-coated Zn symmetric cells were recorded under a −200 mV overpotential. The Zn–AC hybrid supercapacitors were fabricated with AC as the cathode, bare Zn or PAM/PVP-coated Zn foil as the anode, and 3 M Zn(CF3SO3)2 aqueous solution as the electrolyte. The cathode slurry was fabricated by mixing the cathode active materials, Super P, and PTFE at a mass ratio of 80:10:10. The resulting slurry was rolled into a thin film with a thickness of about 120 μm. Finally, the film was cut into discs with a diameter of 10 mm, pressed into a Ti mesh (15 mm in diameter) and dried in a vacuum oven at 100 °C for 6 h. The electrochemical performance was evaluated by cyclic voltammetry on an electrochemical workstation. The galvanostatic charge–discharge processes of the Zn–AC hybrid supercapacitor were recorded on a Neware battery testing system.

Question: What's the anode?
Answer: bare Zn or PAM/PVP-coated Zn foil
The Zn symmetric and Zn–Ti asymmetric cells were assembled as CR2030 coin cells to measure the electrochemical performances. Glass fiber and a 3 M Zn(CF3SO3)2 aqueous solution were used as the separator and the electrolyte, respectively. Before cell fabrication, Ti foil, bare Zn foil and PAM/PVP-coated Zn were cut into disk-shaped electrodes. The symmetric cells consist of two bare Zn foils (or PAM/PVP-coated Zn foils) separated by a glass fiber separator. The cells underwent galvanostatic charge and discharge cycling at a current density of 0.2–10 mA cm−2 on a Neware battery testing instrument. These experiments were performed to evaluate the stripping/plating behavior and cycling stability of the bare Zn and PAM/PVP-coated Zn anodes. Furthermore, Zn–Ti asymmetric cells were fabricated to investigate the coulombic efficiency of Zn stripping/plating. The asymmetric cell was initially discharged for 10 min, and then to 2.0 V at various current densities from 0.2–20 mA cm−2. To obtain the corrosion potential (Ecorr) and corrosion current density (Icorr), Tafel plots of the Zn symmetric cells were recorded on an electrochemical workstation (CHI660E, China) at a scan rate of 10 mV s−1. Chronoamperograms (CAs) of the bare Zn and the PAM/PVP-coated Zn symmetric cells were recorded under a −200 mV overpotential. The Zn–AC hybrid supercapacitors were fabricated with AC as the cathode, bare Zn or PAM/PVP-coated Zn foil as the anode, and 3 M Zn(CF3SO3)2 aqueous solution as the electrolyte. The cathode slurry was fabricated by mixing the cathode active materials, Super P, and PTFE at a mass ratio of 80:10:10. The resulting slurry was rolled into a thin film with a thickness of about 120 μm. Finally, the film was cut into discs with a diameter of 10 mm, pressed into a Ti mesh (15 mm in diameter) and dried in a vacuum oven at 100 °C for 6 h. The electrochemical performance was evaluated by cyclic voltammetry on an electrochemical workstation. The galvanostatic charge–discharge processes of the Zn–AC hybrid supercapacitor were recorded on a Neware battery testing system.

Question: What's the electrolyte?
Answer:  3 M Zn(CF3SO3)2 aqueous solution
Despite the merits of zinc anode, ARZIBs are still at a development stage due to the lack of suitable Zn-ion host materials. To date, various materials have been explored as cathodes for ARZIBs, such as manganese-based oxides, Prussian blue analogues, polyanionic compounds, and vanadium-based compounds. However, most of the reported cathode materials suffer from insufficient rate capability, low capacity, and energy density. The main reasons can be ascribed to three factors: (i) the relativity poor conductivity leads to sluggish ion/electron transport kinetics, especially in quasi-solid-state electrolytes; (ii) the use of non-active additives such as polyvinylidene fluoride and polypyrrole, which were usually employed to ameliorate the flexibility of powder-formed active materials, would inevitably increase the “dead mass” of the cathode, thus limiting the overall energy density of the full devices; (iii) the increased contact resistance between the active materials and the current collector, and the interfacial resistance between the electrode and electrolyte, arising from the repeated reversible Zn2+ (de)intercalation processes, further result in a decrease in the high rate ability. Therefore, there is an urgent demand to explore free-standing materials that can adequately accommodate Zn2+ insertion/extraction rapidly and steadily to promote the progress of ARZIBs.

Question: What's the cathode?
Answer: manganese-based oxides, Prussian blue analogues, polyanionic compounds, and vanadium-based compounds
Despite the merits of zinc anode, ARZIBs are still at a development stage due to the lack of suitable Zn-ion host materials. To date, various materials have been explored as cathodes for ARZIBs, such as manganese-based oxides, Prussian blue analogues, polyanionic compounds, and vanadium-based compounds. However, most of the reported cathode materials suffer from insufficient rate capability, low capacity, and energy density. The main reasons can be ascribed to three factors: (i) the relativity poor conductivity leads to sluggish ion/electron transport kinetics, especially in quasi-solid-state electrolytes; (ii) the use of non-active additives such as polyvinylidene fluoride and polypyrrole, which were usually employed to ameliorate the flexibility of powder-formed active materials, would inevitably increase the “dead mass” of the cathode, thus limiting the overall energy density of the full devices; (iii) the increased contact resistance between the active materials and the current collector, and the interfacial resistance between the electrode and electrolyte, arising from the repeated reversible Zn2+ (de)intercalation processes, further result in a decrease in the high rate ability. Therefore, there is an urgent demand to explore free-standing materials that can adequately accommodate Zn2+ insertion/extraction rapidly and steadily to promote the progress of ARZIBs.

Question: What's the anode?
Answer: zinc