batterydata/battery-device-data-qa huggingface dataset:
To achieve aqueous zinc batteries with high capacity and superior durability, developing a scalable and efficient strategy for preparing an outstanding cathode is of pivotal importance. Herein, porous cobalt/nickel composite hydroxides supported on 3D Co–Ni foam (CNF) are used to construct a robust cathode (denoted as UTCNF) via a facile and cost-effective ultrasonic method that is suitable for scaling up to an industrial level. Attributed to the synergistic effects of the 3D foam architecture, the porous structure, and the in situ formation of electrochemically active cobalt/nickel composite hydroxides, the UTCNF//Zn battery exhibits excellent performance with a relatively high capacity (2.13 mA h cm−2 at 8 mA cm−2), excellent rate performance (47% capacity retention from 8 to 50 mA h cm−2), and superb stability (only ∼10% capacity loss after 30000 cycles at a high current density of 40 mA cm−2). Furthermore, a maximum energy density of 3.99 mW h cm−2 and a peak density of 320 mW cm−2 are also attained. Notably, a soft-package battery that uses the UTCNF as a cathode demonstrates great potential as a power supply. This work may provide valuable ideas for the achievement of large-scale aqueous zinc batteries with high performance.

Question: What's the cathode?
Answer: UTCNF

Question: What's the cathode?
Answer: UTCNF
Long-term cyclic stability of symmetric cells. One of the most promising applications of metal anodes is to combine them with a sulfur or air cathode with a high energy density. It is thus important to find an efficient way of infusing the alkali metal inside the anode scaffold. To introduce Na in the network, the anode was pre-assembled by stacking the CNF film on top of a pure Na foil. The Na foil was manually pressed into a thickness ranging between 200 and 400 μm. The use of this stacked design saved materials and processing time better than the classical sacrificial-cell electrodeposition method. The thickness of Na foil could be further reduced using industrial pressing tools. Fig. 6a presents a schematic of the stacking scheme of the assembled electrode which allowed Na to be effectively stripped and plated by removal and re-infiltration into the fiber network. Fig. 6b presents a side view of the CNF film stacked on top of a Na layer after 6 mA h cm−2 of Na was stripped and re-deposited at a current density of 1 mA cm−2. The image signifies successful re-infiltration of Na in the fiber network after the two-step process. The fiber diameter increased to ∼600–800 nm from the initial ∼150 nm, proving a large load of deposited Na. The final fiber thickness obtained with the stacked design was compatible with the thickness obtained with regular electrodeposition, indicating that a majority of Na was infiltrated from the initial film into the network. In view of the large variation in the measured Na thicknesses, however, it may be possible that some part of Na had been redeposited back onto the original Na film, as shown in the schematics. The above fiber network was likely to hinder any dendritic growth resulting from this scenario. The overall ZNO@CNF film thickness remained at ∼100 μm after infiltration, suggesting that the network could withstand the mechanical pressure inside of the cell while retaining its original shape. The smooth top view of the same anode shown in Fig. S26† indicates that the ZnO@CNF film was able to hold and control the deposited Na even with a high areal loading of 6 mA h cm−2.

Question: What's the cathode?
Answer: sulfur

Question: What's the cathode?
Answer: air
Typically, a certain amount of P(VDF-HFP) powder and BaTiO3 piezoelectric particles (4:1 in m/m) were firstly added into a mixture of N,N-dimethylformamide (DMF) and deionized (DI) water under constant stirring at ambient temperature, forming a well-dispersed solution. The solution was then spread on a clean glass substrate, followed by an immersion in a flowing water bath at 80 °C. Several minutes later, a homogeneous white BaTiO3-P(VDF-HFP) film was obtained and self-peeled off from the glass substrate. Next, the film was dried at 100 °C under vacuum to remove the containing water. Afterwards, the dried film was punched according to the size of the anode or cathode, followed by an appropriate polarization under a DC field of 3.5 kV mm−1 in air atmosphere at ambient temperature for 0.5 h. Finally, the polarized pieces were fully soaked in a liquid electrolyte of 1 mol L−1 NaClO4 dissolved in propylene carbonate (PC) with a 5 vol% fluorinated ethylene carbonate (FEC) additive in a glove box over 24 h, yielding the desired BaTiO3-P(VDF-HFP)-NaClO4 piezoelectric gel-electrolyte.

Question: What's the cathode?

Question: What's the anode?
In 2015, unique graphene-like Co9S8 with a high surface area and hierarchical porosity was first proposed by Nazar's group to afford superior LiPS adsorptivity for high-performance Li–S batteries. The Co9S8/S composite cathode not only manifests up to a factor of 10 increase of cycling stability (0.045% fading per cycle over 1500 cycles at C/2 at a sulfur loading of 1.5 mg cm−2) compared to standard porous carbons but also, more importantly, enables a high-loading sulfur electrode with up to 75 wt% sulfur and up to 4.5 mg cm−2 areal sulfur loading. First-principles calculations and spectroscopic studies consistently demonstrate that a synergistic dual interaction based on Sn2− → Coδ+ and Li+ → Sδ− exists between the metal sulfide-based host material and LiPSs. In particular, it is revealed that the nature of the crystallographic surface plays a very crucial role. The binding energy of 2.22 eV for Li2S2 on the (002) surface (Co/S = 1:4) increases to 3.24 eV for the (202) surface (Co/S = 5:4) and further to 6.06 eV for the purely Co-terminated (008) plane. This finding enables a better understanding of the interaction mechanism for metal sulfides and provides guidance for fabricating host materials with preferred crystal faces, but unfortunately, the mechanism by which the polar surface accelerates LiPS redox has not been clearly revealed yet. Soon after, Yuan et al. demonstrated that simply introducing half-metallic CoS2 microparticles into graphene electrodes largely amplified the electrochemical current response and reduced charge transfer resistance in LiPS symmetrical cells. More importantly, it is found that CoS2 serves as a mediator to provide strong CoS2–polysulfide interaction and to facilitate the liquid–liquid redox of polysulfides, further affecting the correlated liquid–solid transformation, viz., the prior formation of Li2S nuclei. With a sulfur loading of 0.4 mg cm−2, a high initial capacity of 1368 mA h g−1 at 0.5C, an increase of 10% in energy efficiency, and a low decay rate of 0.034% per cycle for 2000 cycles at 2.0C are realized through the incorporation of mechanically milled CoS2 with a low specific surface area. These observations suggest that manipulating the redox reactivity of polysulfides upon a conducting surface is a more effective strategy for improving the Li–S battery performance, in comparison to tuning the dissolvability and transport behavior of polysulfides in aprotic electrolytes. Given that the metal sulfide herein employed is in the bulk form, therefore, the performance enhancement can be further achieved by optimizing its structure and properties, including engineering the crystal facets to mediate the adsorbate–adsorbent interaction, reducing the dimension to maximize the exposed polar surface and introducing a strong coupling effect between substrates and supported metal sulfides for intriguing modulation of material properties.

Question: What's the cathode?
Answer: Co9S8/S composite

Question: What's the anode?
As benchmark inorganic cathodes, we selected a number of materials for non-aqueous cells which, according to the reviews and to the best of our knowledge, are superior in terms of voltage, specific energy/power or cycling stability and are attributed to various material families (hexacyanoferrates, layered oxides, polyanionic compounds, and conversion-type cathodes). The list of benchmarks includes KVPO4F, K2[(VOHPO4)2(C2O4)] (KVPCO), K1.75Mn[Fe(CN)6]·0.16H2O (KMHCF), Fe[Fe(CN)6] (FeHCF), K1.81Ni[Fe(CN)6]0.97·0.086H2O (KNHCF), K0.7Mn0.5Fe0.5O2 (KMFO), K0.51V2O5 and K0.42V2O5·0.25H2O (KVO), and sulfur (S).

Question: What's the cathode?
Answer: hexacyanoferrates, layered oxides, polyanionic compounds, and conversion-type

Question: What's the anode?
Fig. 4d shows the comparison of the rate performances and coulombic efficiencies of the three types of cathodes under different current densities (0.1, 0.2, 0.5, 1.0, and 2.0C). All three cathodes show a coulombic efficiency over 98%, which could be due to the highly conductive CNF skeletons. And, with increasing the current density from 0.1C to 2.0C, the CNF@V2S3/S cathodes can retain a specific capacitance of 922 mA h g−1 (78.9% of the initial value), which is much higher than those of VS2-based LSBs. However, the CNF@VO0.9/S and CNF/S cathodes can retain 390 mA h g−1 (55.1%) and 592 mA h g−1 (68.8%). Here, to gain better understanding of the effect of V2S3 on the rate performances of cathodes, the in situ reaction resistances were first derived from the charge/discharge curves (see the ESI for details†). As shown in Fig. 4e, the reaction resistances of all three cathodes increase with the increasing specific capacity, which is caused by the low conductivity of intermediate LiPSs. Compared to the CNF@VO0.9/S and CNF/S cathodes, the CNF@V2S3/S ones show a much lower reaction resistance along the whole electrochemical processes. And similar results can also be obtained from Electrochemical Impedance Spectroscopy (EIS) spectra (Fig. S14†). This decrease in resistances often leads to fast redox kinetics on the CNF@V2S3/S cathodes. Besides, galvanostatic intermittent titration technique (GITT) tests were further carried out to further study the origins for fast transfer kinetics of CNF@V2S3/S cathodes (Fig. S15†). The diffusivities of Li ions between the cathode and electrolyte were estimated, as listed in Table S2.† The diffusion coefficient of Li+ ions in the CNF@V2S3/S/electrolyte system is 2.857 × 10−6 cm2 s−1, which is much higher than those of CNF@VO0.9/S and CNF/S ones (1.554 × 10−7 and 1.645 × 10−7 cm2 s−1) in this work. This greatly improved diffusivities of Li ions would result in the high specific capacity and the high rate capability of CNF@V2S3/S cathodes. Also, a similar conclusion can be obtained from EIS spectra in the low-frequency region (Fig. S14†). It can be seen that the curve slope of CNF@V2S3/S cathodes is much larger than those of the CNF@VO0.9/S and CNF/S ones (Table S3†).

Question: What's the cathode?
Answer: CNF@V2S3/S

Question: What's the electrolyte?

Question: What's the cathode?
Answer: CNF@VO0.9/S and CNF/S
Moreover, the formation of metal sulfides with a non-crystalline structure also reveals enhanced adsorption/bonding of LiPSs owing to abundant defects and dangling bonds. For example, amorphous TiS4 has been successfully prepared by Sakuda et al. through a mechanical milling process using crystalline TiS2, sulfur, and acetylene black. When used as the cathode in a Li–S battery, the dissolution of LiPSs into the electrolyte is significantly suppressed because amorphization reduces the symmetry of the lattice, leading to the possibility of overlapping electron clouds between sulfur and titanium atoms, resulting in chemical bonding between the elements. Liu et al. reported the synthesis of a S@amorphous NiS2 composite via a coprecipitation reaction using Na2S8 and NiCl2 ethanol solution. Here the soluble sulfide ions can permeate into the loose amorphous structure, and thus the S particle would nucleate and grow in the inner space of NiS2, ensuing the high immobilization of S species. Very recently, Yu et al. meticulously designed hollow-amorphous N-doped carbon/MoS3 nanoboxes (NC/MoS3 NBs) as an advanced sulfur host for Li–S batteries. In a typical synthesis, crystalline α-Fe2O3 nanocubes are first coated with a layer of polydopamine, which are then calcined in a N2 atmosphere and etched in HCl solution to obtain N-doped carbon (NC) shells and hollow NC nanoboxes, respectively. Finally, the NC/MoS3 NB host is prepared through heterogeneous nucleation using CTAB as the surfactant and (NH4)2MoS4 as the precursor. Here, the amorphous MoS3 with unsaturated coordination Mo and electron-rich S not only has strong binding capability to LiPSs but also exhibits a catalytic effect on polysulfide conversion, which are verified by both experimental investigations and theoretical calculations. More interestingly, this synthesis strategy can be generalized to fabricate other amorphous metal chalcogenides nanoboxes such as CoSx and WSx, which is also promising to be applied in the fields of energy storage and conversion.

Question: What's the cathode?
Answer: LiPSs

Question: What's the electrolyte?
Later, Wang et al. published a similar study, using annealed PTCDA as the anode material and 30 M KFSI aqueous solution as the electrolyte. The reversible capacity of PTCDA reached 134 mA h g−1 at 0.2 A g−1. Decent rate and cycling capabilities were demonstrated. A full cell with potassium iron(II) hexacyanoferrate as the cathode delivered 39 mA h g−1 based on the combined mass of the electrodes, and it was almost constant up to 4 A g−1 current density. The capacity retention of the full cell was 89% after 1000 cycles at 2 A g−1.

Question: What's the cathode?
Answer: potassium iron(II) hexacyanoferrate

Question: What's the anode?
Answer: PTCDA

Question: What's the electrolyte?
Answer: 30 M KFSI aqueous solution
In the last few decades, the demand for batteries has rapidly increased in various application fields. Although rechargeable batteries (such as lithium-ion batteries) have become a focus of attention, primary batteries still occupy a large market share in many civilizations and military applications such as portable power sources, signal lights, and space and ocean exploration. As a result, efforts to develop primary batteries with high energy density, high power density, and low cost have never stopped ever since the invention of volt batteries in 18th century. Especially in recent years, large number of batteries with high energy density have been developed, such as the Zn–O2, Mg–O2, Al–O2, Na–O2, and Li–O2 systems. In addition, primary batteries, such as the currently developed Li–SO2, Li–SOCl2, Li–MnO2, and Li-CFx systems, have also been developed under isolated conditions for applications such as ocean and out space. Primary batteries are usually required to have high energy density, long shelf life, stable discharge voltage, and low self-discharge rate and should be readily available for use. Currently, the Li/MnO2 batteries account for more than 80% share of the lithium primary battery market due to their low cost, high safety, and natural abundance of Li and Mn. Moreover, the Li/MnO2 batteries possess a high practical specific energy of 308 W h kg−1 and a long shelf life of about 10 years. However, the application of Li/MnO2 batteries is limited by their poor electrochemical performance at high power output and low temperature, which is ascribed to several issues including low electronic conductivity, low lithium diffusion coefficient, and structural susceptibility of the MnO2 cathode. To address these issues, numerous methods, such as structural design and composite, coating, and metal cation doping, have been studied to optimize the performance of the MnO2 cathode. In addition, to overcome the intrinsic limitations of the current cathode materials, exploring novel cathode materials is a potential strategy for promoting the performance of lithium primary batteries.

Question: What's the cathode?
Answer: MnO2

Question: What's the cathode?
Answer: MnO2
In order to further study the chemisorption of LiPSs on the electrodes, we carried out the visual adsorption experiment of Li2S6 on the CNF@V2S3 cathodes. As shown in Fig. 3g, the dark-yellow colour of Li2S6 solution containing CNF@V2S3 fades in the visible region obviously after 24 h; while the solution containing CNFs, by contrast, almost shows no change in its colour, directly demonstrating that CNF@V2S3 cathodes can anchor LiPSs strongly. Moreover, we also compare the colour change of the polypropylene separators used in the assembled LSBs. As shown in Fig. S6,† after 100 cycles, the separator in the LSBs based on CNF@V2S3 composites almost retains its own white colour; while that based on CNF@V2S3 and CNFs cathodes show an apparent change in colour from white to light yellow, especially that based on CNFs. These visual comparisons of the change in colour again indicate that the CNF@V2S3 composites could greatly inhibit the shuttling of LiPSs between the electrodes. Furthermore, first-principles simulations based on density functional theory (DFT) have been applied to theoretically study the chemisorption behaviours of LiPSs. Fig. 2h shows the adsorption conformation of LiPSs (Li2Sn: n = 2, 4 and 6) on the (204) plane of V2S3. And the Eads between V2S3 and Li2S/Li2S4/Li2S6 were estimated to be 1.29, 0.81 and 1.02 eV, which are much higher than those values of the Eads between C and LiPSs.

Question: What's the cathode?
Answer: CNF@V2S3

Question: What's the cathode?
Answer: CNF@V2S3
Nowadays, a variety of multifunctional electrocatalysts are being developed while there is still a lack of suitable design to fully realize their multifunctionalities. Here, we propose a general, simple, two-component design of an electrolyser to replace the traditional three-component design for decoupled water splitting. Trifunctional (OER, HER and ORR) electrocatalysts (such as nickel sulfide foams with surface grown N-doped carbon nanotube arrays) are used as the gas evolution electrode to replace both the cathode and the anode, while materials with suitable redox activities (NaTi2(PO4)3 or commercial Ni(OH)2) are used as the relay electrode. In such a design, the H2/O2 evolution can be switched by reversing the current polarity, and the ORR before the HER consumes the residual O2 left in the electrolyser, guaranteeing the high purity (∼99.9%) of the as-obtained H2. With NaTi2(PO4)3 as the relay electrode and the nickel sulfide foam as the gas evolution electrode, owing to the high decoupling efficiency of the NaTi2(PO4)3 relay (97%) and the low HER/OER overpotentials of the trifunctional nickel sulfide foam, an energy conversion efficiency of up to 94.3% can be obtained for the as-assembled electrolyser at a current density of 10 mA cm−2. When combined with a commercial Si PV module with an efficiency of 14.4%, the as-designed PV-electrolysis system showed a solar-to-hydrogen conversion efficiency of up to 10.4%. Utilization of trifunctional electrocatalysts greatly reduces the complexity of the electrolyser and the overall cost for electrochemical H2 production, and these electrolysers may potentially be used to construct highly competitive water splitting systems for continuous H2 production and green energy harvesting. Our research may also bring new insights into the utilization of multifunctional electrocatalysts in other devices, such as metal–air batteries and fuel cells.

Question: What's the cathode?

Question: What's the anode?
To better understand the good cycling stability of the full cell in the Na–H2O–urea–DMF electrolyte, inductively coupled plasma emission spectrometry-atomic emission spectroscopy (ICP-AES) analysis of the vanadium concentration in the Na–H2O–urea–DMF electrolyte and analysis of electrochemical impedance parameters were carried out before and after cycling. As shown in Fig. 4b and Table S3,† it is found that the concentration of V-ions in the Na–H2O–urea–DMF electrolyte before cycling is 0.05 μg mL−1. After 50 cycles and after 100 cycles, the concentrations of V-ions in the Na–H2O–urea–DMF electrolyte are 16.65 μg mL−1 and 20.12 μg mL−1, respectively. In 1 M Na2SO4 solution, the concentrations of V-ions are 0.08 μg mL−1, 60.68 μg mL−1 and 72.34 μg mL−1, respectively. Compared to 1 M Na2SO4 solution, the Na–H2O–urea–DMF electrolyte can obviously inhibit the dissolution of the electrode materials. Upon comparison of the V-ion concentrations in NaClO4 solution, Na–H2O–DMF, and Na–H2O–urea electrolyte of the NVP//NTP full cell after 50 cycles (Fig. S14†), it is found that the Na–H2O–urea–DMF electrolyte can suppress the dissolution of V-ions in the charge–discharge process. This result is consistent with the cycling performances of the NVP//NTP full cell in different electrolytes (Fig. S13†). Thus, it can be concluded that the NVP/C cathode is much more stable in the Na–H2O–urea–DMF electrolyte, which is beneficial for the long lifespan of the full cell. Similarly, as illustrated in Fig. S15,† the NTP anode in the Na–H2O–urea–DMF electrolyte displays high coulombic efficiency and good cycling stability relative to that in 17 M NaClO4 and 1 M Na2SO4 solution.

Question: What's the cathode?
Answer: NVP/C

Question: What's the anode?
Answer: NTP

Question: What's the electrolyte?
Answer:  Na–H2O–urea–DMF
A carbon nanotube film was used as the oxygen cathode and Li foil with 0.5 mm thickness as the anode for LOBs. A glass fiber separator wetted with a 100 μL electrolyte composed of 1.0 M LiTFSI in TEGDME was employed to separate the cathode and anode. All assembled cells were measured on a LAND electrochemical testing system at 25 °C. The cycling test was conducted with the capacity limited at 1000 mA h g−1 at a current density of 300 mA g−1.

Question: What's the cathode?
Answer: oxygen

Question: What's the anode?
Answer: Li foil
Co-free Ni-rich cathode materials, particularly LiNiO2 and its doped analogs, face ongoing challenges as the need for commercialization rises. To address surface instability and its associated phenomena, a systematic and accurate understanding is highly required. In this work, we systematically studied the fragile surfaces of the LiNiO2-based cathode materials, with the goal of identifying how experimental conditions may influence characterization results. We presented the challenges in characterizing and analyzing the surface chemistry of LiNiO2-based materials using two comparative cathodes as a model platform, i.e., LiNiO2 versus Mg/Ti–LiNiO2. The surface lithium residuals are inevitable and highly dependent on various sample storage and handling conditions. Due to the highly reactive surfaces, we found that the sample preparation for electron microscopy and surface-sensitive X-ray analyses greatly influences the final observations, resulting in skewed surface chemistry analytical results. We also provided some recommendations regarding how to obtain representative characterization analyses. Using simple comparisons, we further illustrated the advantages of Mg/Ti dual dopants to enhance the surface structural resistance to many circumstances, while corroborating previously reported observations. However, we found that the surface of Mg/Ti–LiNiO2 material still encounters a series of problems caused by the fragile CEIs at elevated temperatures. Efforts should be devoted towards the development of highly stable CEIs either by cathode surface coating, doping, electrolyte modification or combining multiple strategies.

Question: What's the cathode?
Answer: Co-free Ni-rich

Question: What's the cathode?
Answer: LiNiO2-based