batterydata/battery-device-data-qa huggingface dataset:
In order to achieve higher power/energy densities for electrochemical energy storage, dual-ion batteries (DIBs), relying on the migration of both cations and anions to store charge concurrently, have been developed. Compared with lithium ion batteries, dual-ion migration behavior can shorten the charge carrier distance. From a cation perspective, lithium ions, as a charge carrier, have contributed to energy storage for several decades. However, many issues have also been raised, such as safety, excessive resource consumption, and environmental pollution. In the process of searching for substitutes, sodium ions, zinc ions, aluminum ions, and other metal ions have been investigated as charge carriers. Non-lithium electrochemical energy storage systems have shown signs of progress. However, no matter how they were improved, metal dendrites have still remained present during the anodic process. To address this limitation, the non-metal ionic liquid EMIm+[PF6]− has been employed as an electrolyte to realize charge transport. Unfortunately, due to the larger radius of EMIm+ (vertical: 4.3 Å; horizontal: 7.6 Å), it is not possible for traditional graphite anodes to provide a high intercalation capacity. Selecting new electrode materials to achieve the intercalation/deintercalation of EMIm+ can be a route to overcome this bottleneck limitation.

Question: What's the anode?
Answer: graphite

Question: What's the electrolyte?
Answer: EMIm+[PF6]−
To better visualize the local contact loss distribution around the cathode particles, a single NMC particle and its surrounding voids in the sample cycled 50 times were isolated from the larger volume and are shown in Fig. 4(f). The spherical NMC particle at the center is shown in grey, and the surrounding voids are shown in red. The voids are much more concentrated on the right side of the NMC particle, suggesting that the contact loss areas caused by the cathode particle volume shrinking will mostly be on one side of the particle, rather than uniformly distributed around the particle. This is expected because the presence of voids on one side of the particle is sufficient to release the strain caused by the particle volume change. This concentration of the decohered area in the cathode particle may aggravate its effect on capacity loss as now all the Li ions going in and out of the area under the contact loss have a much larger distance to travel before they reach the solid electrolyte. This is in contrast to if the contact loss area were homogeneously dispersed across the cathode particle. In the latter case, diffusion gradients parallel to the surface, resulting from blocked-out surface area for Li to enter or leave the particle, would rapidly fade out in the cathode particle.

Question: What's the cathode?

Question: What's the electrolyte?
Even though the SEI film is supposed to act as an insulator being a barrier for electron transfer, at the initial nucleation stages its structure may favor electron transport. This may occur because of the differences between the amorphous character of nucleating crystals and their bulk theoretical structures, as has been found in some bulk insulator materials where changes in the electronic conductivity were observed in ultra-thin films showing a semiconductor behavior. This capability of conducting electrons of imperfectly formed SEI nuclei and phases could contribute to the growth mechanism that keeps the SEI forming until it reaches hundreds of nanometers. Another important reason for the continuous SEI growth is the presence of radical charged species that result from the SEI reactions and are able to diffuse toward the vicinity of the electrolyte inducing further reactions. Several experimental and theoretical works have studied the various stages of the SEI formation and growth process while other authors have proposed the formation of artificial SEI layers by pretreating the anode before the battery is assembled. For the early stages of the SEI formation it is crucial to improve the understanding of electrolyte decomposition by characterizing the reaction mechanisms of electrolytes typically used in battery systems. It is known that carbonate solvents have low stability when implemented with Li-metal anodes, while ether-based solvents like dimethoxyethane (DME) and dioxalane (DOL) have shown better stability with respect to the Li-metal anode and are frequently used for these battery systems. However, solvent and salt molecules decomposition are still observed and in spite of the advances reached both from experimental and theoretical studies, the mechanisms of these processes are not yet well understood.

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

Question: What's the electrolyte?

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

Question: What's the anode?
Answer: hard carbon

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

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?

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

Question: What's the anode?
Answer: the bare Zn and PAM/PVP-coated Zn

Question: What's the electrolyte?
Answer: 3 M Zn(CF3SO3)2 aqueous solution

Question: What's the anode?
Answer: bare Zn or PAM/PVP-coated Zn foil

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

Question: What's the anode?
Answer: zinc

Question: What's the electrolyte?
The electrochemical performance of the PAM/PVP-coated Zn–AC hybrid ion supercapacitors was tested by cyclic voltammetry and galvanostatic charge–discharge tests within the voltage range of 0–2.0 V (Fig. 5). The CV curves of the hybrid ion capacitors at various scan rates from 10 mV s−1 to 200 mV s−1 maintain a quasi-rectangular shape, suggesting an EDLC-type behavior (Fig. 5a). Fig. 5b shows the voltage curves of the PAM/PVP-coated Zn–AC hybrid ion supercapacitors at various current densities from 0.5–30 A g−1. The symmetric and linear shape of the curves in the graph can be observed corresponding to the results of the CV test. At a current density of 1 A g−1, the bare Zn–AC hybrid ion supercapacitors failed after 10 cycles, while the PAM/PVP-coated Zn–AC hybrid ion supercapacitors show a good cycling stability (Fig. S10†). This superior stability can be attributed to the critical role of the PAM/PVP layer coated on the zinc anode acting as an inhibitor on the O2/water interphase and a distributor of ions during the zinc deposition. The PAM/PVP-coated Zn–AC hybrid ion supercapacitors show an excellent rate capability of 336, 292, 264, 232, 220, 195, 190, 175, and 165 F g−1 at a current density of 0.5, 1, 2, 5, 8, 10, 15, 20, 25, and 30 A g−1 (Fig. 5c and S11†). The galvanostatic charge–discharge curves and long cycling stability of the PAM/PVP-coated Zn–AC hybrid ion supercapacitors at a current density of 15 A g−1 are shown in Fig. 5d and e. The specific capacitance of the devices slightly increases at first due to activation, then remains quite stable, and ultimately gives a high retention of 100% of the initial specific capacitance after 6000 cycles. These results further demonstrate the excellent electrochemical performance of the Zn–AC hybrid ion supercapacitors with the PAM/PVP layer. Notably, the PAM/PVP-coated Zn–AC hybrid ion supercapacitors have a high energy density of 118 W h−1 kg−1 and a power density of 17.9 kW kg−1 (based on the mass of AC materials, Fig. S12†), where the energy density is superior to those of the bare Zn–AC hybrid ion supercapacitors (Fig. S13 and Table S1†).

Question: What's the anode?
Answer: zinc

Question: What's the electrolyte?
The intermediate LiPSs generated from charge/discharge processes can spontaneously dissolve into the electrolyte and freely migrate between the cathode and the anode through the separator, resulting in the loss of active materials, passivation of both the electrodes, and unavoidable self-discharge/recharge. So far two typical strategies covering physical confinement and chemical adsorption have been proven and generally accepted as an effective solution to address this issue. Physical confinement often relies on the high surface area or pore structure of the host materials, while chemical adsorption depends on the strong interaction between the host materials and LiPS species. Accordingly, rationally creating metal sulfides with a desired surface area, well-designed porosity, enhanced surface polar/selectivity, and tailored crystalline form has been achieved by a variety of approaches, e.g. solvothermal/hydrothermal methods, ball-milling technology, coprecipitation method, and innovative heat treatment technology.

Question: What's the cathode?

Question: What's the anode?

Question: What's the electrolyte?
Bulk heterojunction (BHJ) polymer solar cells (PSCs) that convert absorbed sunlight into electrical energy have been in the spotlight due to their potential in large-scale and cost-effective roll-to-roll fabrication. In the past decade, massive endeavors concerning the development and interfacial engineering of novel light-harvesting materials have been made to improve the power conversion efficiency (PCE). Nowadays, the highest PCE exceeds 16% for single-junction BHJ PSCs. Interface layers, positioned between the photoactive layer and the anode/cathode electrode, play vital roles in governing the performance of PSCs. Interface layers are usually utilized to tailor the work function of the electrode for charge carrier collection maximization, modify the interface to alter the photoactive layer micromorphology, as well as minimize carrier recombination at the interfaces between the active layer and the transport layer. For a hole transport layer (HTL), pivotal parameters consist of high conductivity, high transparency, solution processability, favorable stability, etc. PEDOT:PSS, as the state-of-the-art hole transport material in organic optoelectronic devices, possesses outstanding edges of high transmittance in the visible spectrum and superior film-forming ability and thermal stability. However, PEDOT:PSS solution is strongly acidic and hygroscopic, which can etch the indium tin oxide (ITO) anode. Moreover, it has been verified that the spin-casted PEDOT:PSS thin film often exhibits inhomogeneous morphology and poor electrical conductivity, leading to poor efficiency and stability of devices. The development of a PEDOT:PSS HTL that possesses interconnected conductive domains and enhanced electrical conductivity is crucial to PSCs.

Question: What's the cathode?

Question: What's the anode?
Answer: indium tin oxide (ITO)

Question: What's the electrolyte?
LiMn2O4 (LMO) was used as a cathode to evaluate the electrochemical performance of Al2O3-coated LTO in the WiSE (Fig. S5†). The mass ratio of LMO:LTO was set as 2.5:1 to accommodate the low CE of LTO during the initial several cycles. 1C was used instead of a high rate to demonstrate the stability of the electrolyte in the full cell. Such LTO/LMO full cells delivered a voltage plateau at ∼2.4 V during discharge. The discharging capacity based on LTO mass was 145 mA h g−1. In the first cycle, a coulombic efficiency (CE) of 84.5% was delivered, indicating that a relatively small amount of electrolyte was consumed to form an additional LiF-rich SEI on the Al2O3-coated LTO anode. In comparison, pairing the uncoated LTO and LMO delivered a CE of 50% (Fig. S6†), further confirming the effect of the Al2O3 coating in suppressing the side reaction. As we reported previously, the reduction of salt anions bis(trifluoromethane sulfonyl)imide (TFSI) occurs between 1.9 V and 2.9 V. Although reduction of TFSI anions is expected to occur if an Al2O3 coating is absent (Fig. S7†), formation of a complete SEI needs a long time (i.e., few cycles in galvanostatic charge/discharge cycles). The lithiation potential of pristine LTO resides beyond the cathodic limit of the WiSE, so a significant HER will occur before lithiation. The persistent evolution of gas undoubtedly prevents complete formation of the SEI. For the initial cycles, when a robust SEI has not been constructed, protection of the Al2O3 surface serves as a key barrier to ensure that SEI chemistry occurs, and that the SEI ingredient formed from the reduction of the TFSI anion adheres to the anode surface. After the most challenging period in the initial cycles, a dense and complete SEI will come into shape (Fig. S7†), eventually providing long-term protection and allowing LTO to deliver a reversible capacity.

Question: What's the cathode?
Answer: LiMn2O4 (LMO)

Question: What's the anode?
Answer: Al2O3-coated LTO

Question: What's the electrolyte?
3Mg/Mg2Sn electrodes were subjected to galvanostatic C/D at various rates in Mg(HMDS)2/MgCl2. In addition to the unprecedented high capacity, the rate performance of 3Mg/Mg2Sn was also impressive. The stepwise increase in C/D rates resulted in a continuous decrease in reversible capacities, but the degree of reduction was not abrupt (Fig. 5A). For example, a reversible capacity of 805 mA h g−1 was delivered at 100 mA g−1 and as much as 87 and 53% (700 and 430 mA h g−1) of it was retained at 500 and 1500 mA g−1, respectively. Accordingly, the corresponding C/D profiles also showed a relatively small increase in overpotentials with an increase in the C/D rates (Fig. 5B). When compared with the plateau voltage at 100 mA g−1, the additional overpotential required at 1500 mA g−1 was only ca. ±50 mV. It should be stressed here that such excellence has never been reported for either alloy- or intercalation-type electrodes in MIBs. Most anode materials show a capacity of less than 400 mA h g−1 at a C/D rate lower than 100 mA g−1, which significantly decreases with increasing C/D rates (Table 1). A few materials can deliver reasonable capacities at high rates, but no performance has been comparable to that of 3Mg/Mg2Sn.

Question: What's the anode?

Question: What's the electrolyte?
Electrochemical impedance spectroscopy (EIS) curves are presented in Fig. S8.† A larger slope, which is associated with the Warburg impedance (Ws), was observed in the low-frequency region of the curve of the Fe-intercalated ML Ti3C2Tx electrode. Such an occurrence is related to the migration of electrolyte ions within the electrode. It is inferred that the faster kinetics of EMIm+ were derived from the increased space caused by Fe pre-intercalation. Ex situ Ti 2p and Fe 2p XPS spectra are presented in Fig. S9;† no obvious shifts were observed. This finding indicates that the charge storage mechanism of the Fe pre-intercalated ML Ti3C2Tx anode is based on the intercalation/de-intercalation behavior of EMIm+ instead of a redox process. Therefore, the larger real interlayer space contributed to the enhanced electrochemical performance. The scheme in Fig. 5d shows the charge storage mechanism of this DIB. Upon charging, EMIm+ cations were inserted into Fe pre-intercalated ML Ti3C2Tx, whereas PF6− anions were intercalated into the graphite cathode. Charge–discharge profiles of the full DIB are presented in Fig. S10†. The DIB provided an energy density of 76 W h kg−1 at a power density of 360 W kg−1. The cycling stabilities and capacity retentions of the electrodes were examined via performing GCD tests at the same current density. After 50 cycles, the DIB retained 94% of its initial capacity (Fig. 5e), indicating its improved stability compared with a DIB using the ML Ti3C2Tx anode (71%). Ragone plots are presented in the inset of Fig. 5e. The full DIB displayed a good rate capacity, with energy densities of 76, 70, and 64 W h kg−1 at power densities of 360, 900, and 1800 W kg−1, respectively. However, when the power density was higher than 3600 W kg−1, the energy density was reduced. The dual-ion intercalation mechanism of this DIB provides a new route for multi-ion storage.

Question: What's the cathode?
Answer: graphite

Question: What's the anode?
Answer: ML Ti3C2Tx

Question: What's the anode?
Answer: ML Ti3C2Tx