batterydata/battery-device-data-qa huggingface dataset:
In this paper, MoP and NiCo-LDH are used to synthesize a composite of MoP@NiCo-LDH, which is supported on nickel foam to form a bifunctional composite catalyst (abbreviated as MoP@NiCo-LDH/NF), as shown in Fig. 1. During the synthesis, different electrodeposition times are used to optimize the catalyst's performance toward both UOR and HER. Both instrumental characterization and electrochemical measurements confirm that the composition between MoP and NiCo-LDH as well as their electrodeposition onto the NF surface can increase the material's specific surface area and produce a synergetic effect toward high performance. To validate this bifunctional catalyst, a two-electrode electrolyser (MoP@NiCo-LDH/NF-20‖MoP@NiCo-LDH/NF-20) with this catalyst on both the anode and the cathode was designed and constructed, and the test results show that this catalyst has better catalytic performance than that of a Pt/C/NF‖IrO2/NF electrolyser, where noble metal materials (Pt and IrO2) are used as the catalysts.

Question: What's the cathode?

Question: What's the anode?
Fig. S3d† and 4d display cyclic voltammogram (CV) curves obtained using the S-C(PAN) anode with bare LMO and LMO-30 min in the potential range of 1.0–3.2 V at a scan rate of 0.1 mV s−1, respectively. One peak is observed in both positive and negative scans in both samples. For the LMO-30 min cathode, a more pronounced peak appearing at 2.63 V in the first positive scan is observed and the peak is shifted to 2.45 V in the subsequent cycles. The peak of the negative scan appears at 1.77 V as depicted in Fig. 4d, which shows that PVDF@LGLZNO does not practically involve in the redox reactions of the tested voltage range, thus the composite coating must be stable and did not contribute to the capacity. The large polarization between the peaks in the first and following cycles is due to SPAN activation energy and the SEI formation. This means that more energy is needed to dissociate the sulfur atom from the pyridine-derivative, which is usually termed as the unique activation process of sulfurized polyacrylonitrile.

Question: What's the cathode?
Answer: LMO

Question: What's the anode?
Answer: S-C(PAN)
Fig. 3 shows the electrochemical performances of a half-cell in a three-electrode system and a NVP//NTP full cell. As shown in Fig. 3a and b, the NVP half-cell exhibits a pair of redox peaks with good symmetry at 0.68 V and 0.42 V vs. Ag/AgCl, which can be ascribed to the reversible conversion of the V3+/V4+ couple, corresponding to the reversible extraction/insertion of Na+ in the NVP electrode. The half-cell delivers a specific charge and discharge capacity of 110 mA h g−1 and 96 mA h g−1 in the first cycle, and exhibits good reversibility for the first time. The irreversible charge capacity mainly resulted from the dissolution of the V-ions until the appearance of O2 evolution which was recorded in CV curves. For NTP, a pair of Ti4+/Ti3+ redox peaks at −0.55 V and −0.82 V vs. Ag/AgCl can be found in the CV curves. As seen in Fig. 3c, the CV curves show that the hydrogen evolution reaction still does not occur when the potential is −1.1 V vs. Ag/AgCl, which suggests that the Na–H2O–urea–DMF electrolyte can inhibit the side reaction well. As shown in Fig. 3d, the NTP in the Na–H2O–urea–DMF electrolyte delivers a pristine discharge capacity of 118 mA h g−1, concurrently exhibiting a perfect platform and good reversibility, which is better than that of a NTP anode with cationic doping. As shown in Fig. S10 and S11,† the NTP anode exhibits an impressive cycling stability in a conventional non-aqueous electrolyte. However, the coulombic efficiency and cycling performance of the NVP cathode at 2C in a conventional non-aqueous electrolyte are poor due to the dissolution of V-ions and change of structure.

Question: What's the cathode?
Answer: NVP

Question: What's the anode?
Answer: NTP

Question: What's the anode?
Answer: NTP
In this study, a flexible self-charging sodium-ion full battery (SCSFB) was feasibly designed by employing self-synthesized Na3V2(PO4)3@C as the cathode, commercial hard carbon as the anode, and a flexible BaTiO3-P(VDF-HFP) film immobilized with a liquid electrolyte of NaClO4 as the built-in piezoelectric gel-electrolyte (BaTiO3-P(VDF-HFP)-NaClO4). Owing to the excellent compatibilities of the electrodes, the flexible SCSFB delivers reasonable electrochemical performance including large specific capacity and stable cyclability. Besides, external mechanical energy from the ambient environment can also be simultaneously collected and stored via a persistent self-charging mode, whether with static compression, repeated bending or continuous palm patting. This work paves a feasible way to the achievement of sustainable sodium-ion full batteries with high flexibility and enhanced safety for wearable electronics that come into direct contact with human tissues.

Question: What's the cathode?
Answer: Na3V2(PO4)3@C

Question: What's the anode?
Answer: hard carbon
ssZIBs are composed of four components including a cathode, an anode (zinc metal), a solid electrolyte and current collectors. The gel electrolyte is sandwiched between the cathode and anode. Each component has a significant effect on the performance of the whole battery. Currently, various gel electrolytes have been studied and have been applied in ZIBs. However, the performance of ssZIBs is still not comparable with that of the batteries using liquid electrolytes, especially high rate capability, due to the low ionic conductivities of gel electrolytes. To realize high ionic conductivity, an ideal gel electrolyte requires a high-water content and efficient ion migration channels, combined with reasonable mechanical properties. As one of the principal natural polymers, cellulose nanofibers (CNFs) are widely used as a sustainable reinforcing additive in various composites. In addition, the hydrophilic skeleton of CNFs and their three-dimensional fiber network with a large space can help stabilize the channels for charge transportation. Furthermore, due to the abundant hydroxyl groups on the surface of CNFs, it is facile to link the CNFs with polyacrylamide (PAM) molecular chains through hydrogen bonding. The combination of CNFs and PAM can serve as an effective solid electrolyte with good mechanical properties and high ionic conductivity. Due to the high thermal stability of hydrogel polymers, ssBs are also able to operate under both low and high temperature conditions, which is critical for the application of batteries in some harsh environments such as cold/frozen regions and flying airplanes in space.

Question: What's the cathode?

Question: What's the anode?
Answer: zinc metal
To study the catalytic performance of MoS2, the potentiostatic reduction of Li2S8 (10 mM based on sulfur in tetraglyme solution) was conducted on CF-based current collectors. Here, 25 μL Li2S8 was dropped onto the CF, MoS2 sheet/CF, and MoS2 ND/CF current collectors as the cathodes. CR2032 coin cells were assembled using as-prepared cathodes, Li metal anodes, Celgard separators, and 25 μL 0.5 M LiTFSI tetraglyme electrolyte. The cells were discharged to 2.06 V at 0.112 mA, to reduce all the long chain polysulfides to Li2S4. Then, the cells were kept potentiostatically at 2.05 V to drive the nucleation and growth of Li2S until the current dropped below 10−5 A. The current–time curves were integrated based on Faraday's law to evaluate the capacities from the precipitation of Li2S on the various current collectors. To study the morphology of the precipitated Li2S, the operated cells were dissembled in a glovebox and washed with flooded DME before taking them for SEM observation.

Question: What's the cathode?
Answer: CR2032 coin cells

Question: What's the anode?
Answer: Li metal

Question: What's the electrolyte?
Answer: 25 μL 0.5 M LiTFSI tetraglyme
Fig. 5b and d display the images of S-C(PAN) anodes cycled with bare LMO and LMO-30 min, respectively. Also, the images of S-C(PAN) anodes cycled with PLMO-10 min and LMO-10 min are shown in Fig. S4b and d.† The morphologies of cycled S-C(PAN) electrodes with bare LMO, PLMO-10 min, and LMO-10 min electrodes seem rough with obvious cracks. In contrast, Fig. 5d displays the smooth surface of the S-C(PAN) electrode with no severe cracking. The surface feature and integrity are believed to be related to the manganese dissolution of the LMO cathode and the re-deposition on the anode surface, which will be discussed in detail in the following text.

Question: What's the cathode?
Answer: LMO

Question: What's the anode?
Answer: S-C(PAN)

Question: What's the anode?
Answer: S-C(PAN)
Here, we demonstrate a new method to modify the surface of an LMO electrode for the first time. A stabilized LMO cathode was achieved by the electrospun coating of PVDF and gallium (Ga) and niobium (Nb) co-doped LLZO (Li5.6Ga0.26La2.9Zr1.87Nb0.05O12, LGLZNO). The PVDF@LGLZNO fibrous film coating acts as an effective artificial CEI to suppress the manganese dissolution and significantly minimize the undesirable interfacial reaction between the cathode and electrolyte. The improved LMO was further verified by coupling with an S-C(PAN) composite anode to realize stable rate performance and long cycling stability.

Question: What's the cathode?
Answer: LMO

Question: What's the anode?
Answer: S-C(PAN) composite

Question: What's the electrolyte?
Increasing the areal sulfur loading and decreasing the amount of electrolyte in cathodes are natural methods to meet the above requirements. However, thick sulfur electrodes suffer cracking and peeling off problems during slurry casting, thus damaging the electrode integrity. Another obstacle for thick electrodes is the poor immersion of the electrolyte, which restrains the effective sulfur utilization. A promising alternate approach is to use a polysulfide solution, designated as a catholyte, as the starting material. The liquid catholyte is ready to immerse and envelope the surface of the conductive host, thus facilitating rapid charge transfer at the electrode/electrolyte interface, and giving rise to fast reaction kinetics. In addition, highly concentrated catholytes possess an intrinsically low E/S ratio. For example, the E/S ratio of 1.5 M Li2S6 catholyte is only 3.5 μL mg−1, which is difficult to achieve in sulfur particle electrodes. However, the flooded amounts of LPSs in carbon/catholyte electrodes induce a severe shuttling effect due to the poor interaction between the nonpolar carbon host and polar LPSs, leading to a short cycle life. Thus, introducing polar electrocatalysts in carbon/catholyte becomes imperative.

Question: What's the cathode?

Question: What's the electrolyte?
The fabrication of the nanomesh-based cathodes is performed in several steps, starting from the formation of the AAO template, growth of the nanomesh, deposition of the active material precursor and finally its activation by reaction with a lithium source (Fig. 1). In our approach, we focused on lithiated manganese oxides (here, generally abbreviated as LMO) as the active cathode material since they can be synthesized at relatively low temperatures and their precursor (MnO2) can be easily conformally electrodeposited onto high aspect ratio structures. This made LMO the natural choice for demonstrating the potential of nanomesh-based electrodes for Li-ion batteries. It is worth noting that LMO also show a relatively high reduction potential vs. Li+/Li (for example, ∼2.9 V for the layered LiMnO2 and 4–3 V for spinel LiMn2O4 ( ), are cheap and not toxic, but suffer from limited stability when cycled in liquid electrolytes.

Question: What's the cathode?
Answer:  lithiated manganese oxides

Question: What's the cathode?
Answer: LMO
In order to evaluate the electrochemical performance of the obtained electrodes, two-electrode Zn–MnO2 batteries were assembled using COG@MnO2 as the cathode and COG@Zn as the anode in an aqueous electrolyte containing 2 M ZnSO4 and 0.1 M MnSO4. The typical cyclic voltammetry (CV) curves of the aqueous COG@MnO2//COG@Zn battery at different scan rates are shown in Fig. 3d. There are two reduction peaks at around 1.2 and 1.4 V, which should be ascribed to the zinc insertion into MnO2 and the subsequent reduction of Mn(IV) to the Mn(III)/Mn(II) states. Similarly, the oxidation peak and shoulder appear at 1.6–1.8 V, corresponding to Zn-extraction from the MnO2 cathode as the Mn(III)/Mn(II) states undergo oxidation to the Mn(IV) state. The overall reaction of the battery can be formulated as follows:

Question: What's the cathode?
Answer: COG@MnO2

Question: What's the anode?
Answer: COG@Zn

Question: What's the electrolyte?
Answer: 2 M ZnSO4 and 0.1 M MnSO4
In summary, MoP was synthesized on nickel foam, on which NiCo-LDH was electrodeposited to form catalyst electrodes (MoP@NiCo-LDH/NF-x), where x represents the electrodeposition time period, and they were explored as bifunctional catalysts for both the hydrogen evolution reaction (HER) at the cathode and the urea oxidation reaction (UOR) or the oxygen evolution reaction (OER) at the anodes of urea–water or water electrolysis. The morphology and catalytic performance were investigated using a series of physical characterization and electrochemical tests. The results show that at an electrolysis current density of 100 mA cm−2, the anode potential of the MoP@NiCo-LDH/NF-20 electrode is 1.392 V (vs. RHE) for UOR, 233 mV less than that of an IrO2/NF electrode (1.625 V); and the cathode potential of the MoP@NiCo-LDH/NF-20 electrode is 0.255 V (vs. RHE) for HER, closest to that of IrO2/NF (170 mV). For the two-electrode electrolyser (MoP@NiCo-LDH/NF-20‖MoP@NiCo-LDH/NF-20), the cell voltage is as low as 1.405 V for urea–water electrolysis and 1.697 V for water electrolysis at a current density of 100 mA cm−2, even lower than those of a Pt/C/NF‖IrO2/NF cell. Moreover, after 20 hours of continuous electrolysis, the performance and morphology of the catalyst are almost unchanged, indicating that it has both high activity and stability. The results show that the developed MoP@NiCo-LDH/NF-20 is a promising bifunctional catalyst.

Question: What's the cathode?
Answer: MoP@NiCo-LDH/NF-20

Question: What's the anode?
Answer: MoP@NiCo-LDH/NF-20 electrode

Question: What's the electrolyte?
Recently, the atomic-level thickness and large surface area of 2D materials are beneficial to the generation of carriers on the surface and separation of photogenerated carriers. Typically, in comparison to their 3D counterparts, 2D materials present extremely numerous active sites, high carrier mobility, and controllable interface, which offer a large number of advantages for catalysts, electronics, optoelectronics, etc. Among them, penta-type materials have been developed as a series of novel 2D materials. For instance, Yang et al. reported a novel 2D material, penta-Pt2N4, with a large direct band gap, high carrier mobility and high Young's modulus, suggesting numerous potential applications in nanoelectronics. Xiao et al. found that penta-graphene shows desirable electrochemical performance and it may be a potential candidate for Li/Na-ion battery anodes. However, bulk pyrite-SiAs2 has been synthesized under high pressure and validated as a semiconductor decades ago. Meanwhile, this type of pyrite structure can form a 2D penta structure after cleaving the plane, but 2D penta-SiAs2 has not yet been explored.

Question: What's the cathode?

Question: What's the anode?
Answer: penta-graphene

Question: What's the electrolyte?
For electrochromic applications, the device shows rapid, self-powered color switching and multicolor display (color switching from light yellow to transparent, light red, dark green, dark blue and black, corresponding to the combination of the different states of the two films). As an energy storage device, the as-assembled device provides three different open-circuit potentials with an overall areal capacity of up to 933 mA h m−2. Meanwhile, the utilization of the mixed Al/Li-ion electrolyte and the addition of PEDOT:PSS into the inorganic materials greatly promote the cycle stability of the cathode films. Such a new design of the EES device with multicolor display, large charge capacity and high cycle stability can be promising for future color switching/energy storage applications, which may also provide new insights into the design of multifunctional devices.

Question: What's the cathode?

Question: What's the electrolyte?
Answer: mixed Al/Li-ion
A pre-lithiated MCMB anode (Fig. S9†) is utilized to match the LLOs cathode for assembling full cells. Since the matched capacity ratio of the anode/cathode is about 1.1 in the full cells, the specific capacity is evaluated based on the weight of the LLO cathode, while the energy density is calculated based on all the components of the full cell. The electrochemical performance of MCMB|LLO full cells is shown in Fig. 5. The full cells show specific capacities of 270 and 256 mA h g−1 at the cut-offs of 4.7 V and 4.5 V with initial coulombic efficiencies of 81.2% and 84.5%, respectively. As exhibited in Fig. 5(b–f), the full cells exhibit a rapid decay of discharge capacity with a capacity retention of only 61.2% after 100 cycles at 0.5C at the cut-off of 4.7 V. By contrast, the full cells show a much enhanced cycling stability with a capacity retention of 84.5% at the cut-off of 4.4 V after the same cycling period. Also, the full cells cycled at 4.4 V show low electrochemical polarization (Fig. S10†), corresponding to the stable discharge voltage as shown in Fig. 5(f). All the components of a typical pouch full cell are shown in Fig. S11,† and the mass fraction of the cathode in a LIB full cell reaches ∼35%. High energy densities of ∼320 and 305 W h kg−1 are achieved for the MCMB|LLO full cells at the cut-offs of 4.7 and 4.4 V, respectively. If a high-capacity Si/C anode is utilized, the energy density of the full cells can be further enhanced. Improved cycling stability of energy density is also confirmed for the full cells cycled at the cut-off of 4.4 V (Fig. 5(f)). The rate capabilities of the MCMB|LLO full cells at the cut-offs of 4.7 V and 4.4 V are illustrated in Fig. 5(d and e) and S12.† The full cells cycled at the cut-off of 4.4 V deliver reversible capacities of 204.6, 186.1, 152.0, and 125.2 mA h g−1 at the high rates of 1C, 2C, 5C and 10C, respectively, which are much higher than those of cells cycled at the cut-off of 4.7 V. Similar to half cells, the full cells exhibit improved electrochemical performance at the low cut-off of 4.4 V. The performance of MCMB|LLO full cells can be further improved by optimizing the electrolyte, capacity ratio of the anode/cathode, prelithiation and full cell design in future studies.

Question: What's the cathode?
Answer: LLOs

Question: What's the anode?
Answer: MCMB

Question: What's the anode?
Answer: Si/C
As illustrated in Fig. 2a, the TDAC possesses a 2π electron aromatic system that can readily undergo a single electron redox reaction to generate the corresponding TDAC radical dication. Fig. 2b presents the redox potential and solubility of TDAC salt in comparison with those of the state-of-the-art high-potential shuttle molecules. Ideally, the redox potential (protection potential) should be ∼0.2–0.3 V above the upper cut-off voltage of LIBs (normally at 4.3 V). A lower or higher potential outside the range would have the risk of escalated self-discharge during normal operation or an irreversible decomposition of battery components during overcharging. Additionally, a high solubility is desirable since it determines the maximum shuttling current. In these regards, TDAC outperforms all other shuttle candidates with the adequate redox potential of 4.55 V (vs. Li+/Li) and the highest solubility of 0.5 M (Fig. S2†). The electrolyte viscosity before and after the TDAC addition was also investigated. The concentration of 0.2 M was found to be the optimal amount. The viscosity of 0.2 M TDAC electrolyte is 2.72 mPa compared with 2.43 mPa of baseline electrolyte. The electro-kinetics of the TDAC was next investigated by cyclic voltammetry (CV) analysis as shown in Fig. 2c. Even with a high scan rate of 200 mV s−1, TDAC still exhibited a pair of well-defined redox peaks, implying a fast mass transport process within the bulk electrolyte. As shown in Fig. 2d, the diffusion coefficient of TDAC is determined to be 6 × 10−6 cm−2 s−1, which is very comparable with that of other reported shuttles. As displayed in Fig. 2e, after 1000 CV scans, the potential gap between the anodic and cathodic peaks becomes only 60 mV wider, and there is no obvious deterioration of the peak current intensity. Such excellent electrochemical stability has rarely been reported among other 4V-class shuttles. The inset photograph in Fig. 2e presents a shiny Li surface with no bubble generation after storing in TDAC-containing electrolyte solution for six months, indicating a high chemical inertness of the TDAC toward Li metal.

Question: What's the electrolyte?
Answer: 0.2 M TDAC

Question: What's the electrolyte?
Answer: TDAC-containing
To meet the ever-increasing energy storage demand in electric vehicles and stationary storage systems, a substantial increase in the energy densities of the current Li-ion batteries (LIBs) is essential. This motivates researchers to develop alternate chemistries superior to those based on conventional LiFePO4 and LiCoO2 cathode materials. In this regard, Li–S batteries stand out among their peers because of their high energy capacity. Li–S batteries operate via a conversion based reduction reaction of sulfur (S) with Li (16Li+ + S8 + 16e− ↔ 8Li2S), leading to an exceptionally high theoretical energy density of ∼2500 W h kg−1—five times more than that of conventional LIBs (387 W h kg−1 for LiCoO2/graphite batteries). Additionally, the abundant availability and environment friendly nature of S makes it an attractive cathode material. Despite enormous potential, the practical application of Li–S batteries with liquid electrolyte systems is hindered by issues such as large volumetric changes of S and Li2S (∼80%), and the insulating nature of S and Li2Sx. The reduction of S to Li2S during the discharge cycle follows a multistep reduction reaction process, including the formation of highly soluble long-chain polysulfides (Li2Sn, 4 ≤ n ≤ 8), which are produced as intermediates of this process. Such polysulfides shuttle towards the Li anode which leads to chemical short-circuits and an unstable SEI formation on the Li anode. These polysulfides dry out the liquid electrolyte during long-term cycling which severely affects the performance of the cell. The situation is further complicated by the high loading of S on the cathode (>70% S loading, >3 mgsulfur cm−2) during cycling, which intensifies polysulfide dissolution and volume changes, and enforces structural and morphological variations. Overall, such characteristics of the Li–S system result in self-discharge phenomena, poor capacity retention and low coulombic efficiency. On the other hand, the instability of Li anodes with organic liquid electrolytes is also well-known. Li forms mossy or needle like dendritic structures upon cycling which can potentially pierce the conventional polypropylene separators, resulting in internal short circuits of the cells. To solve these problems, various strategies have been explored for both the S and the Li electrodes. For example, synthesizing S composites with carbonaceous materials and/or surface coating the cathodes with conducting polymers have helped in trapping polysulfides. Tuning the properties of organic electrolytes using different additives has been beneficial too. On the Li side, efforts include ex situ coating of Li with polymer- and carbon-based materials or formation of artificial solid–electrolyte interface (SEI) layers to protect the Li electrode from reacting with the organic liquid electrolyte.

Question: What's the cathode?
Answer: LiFePO4

Question: What's the anode?
Answer: Li

Question: What's the electrolyte?

Question: What's the cathode?
Answer: LiCoO2

Question: What's the anode?
Answer: Li