milerssliu/battery-device-data-qa huggingface dataset:
In summary, we have reported a facile strategy for preparing Pt3Ni1/NixFe LDHs as a binder-free catalytic electrode for HSABs. The HSAB with the Pt3Ni1/NixFe LDHs cathode delivered a higher open circle potential of 2.98 V and a lower ΔV of 0.50 V, together with remarkable cycling stability and excellent rechargeability with an average high round-trip efficiency of 79.9% during 350 cycles, which outperforms the HSABs assembled with the commercial catalyst composed of 20% Pt/C and RuO2. The remarkable charge–discharge performance and long-term cycling stability are mainly ascribed to the following: (1) the abundant Ni2+ vacancies alter the surface electronic structure of NiFe LDHs, which promotes electron/ion transfer kinetics and induces the strong interactions with PtNi nanoalloys. (2) The uniformly dispersed ultrafine PtNi nanoparticles on Pt3Ni1/NixFe LDHs enhance the electronic conductivity and provide abundant catalytic active sites, thus greatly boosting the ORR and OER in an alkaline medium. (3) The 3D hierarchically porous architectures of Pt3Ni1/NixFe LDHs offer high integrity and durability, high accessibility for electroactive sites, and enhance the interfacial kinetics that facilitates media transfer, as well as prevent catalytic by-product aggregation. (4) The binder-free design is conducive to exposing more active sites, leading to good catalytic performance. Thus, we believe that the discovery of the bifunctional Pt3Ni1/NixFe LDHs electrocatalyst sheds new light on the rational design of high-performance binder-free catalytic electrodes for large-scale application in energy conversion and storage.

Question: What's the cathode?
Answer: Pt3Ni1/NixFe LDHs
Lithium manganese oxide (LMO) is one of the most promising cathode materials for lithium-ion batteries. However, the dissolution of manganese and its deposition on the anode surface cause poor cycling stability. To alleviate these issues, a film composed of polyvinylidene difluoride (PVDF) and Li5.6Ga0.26La2.9Zr1.87Nb0.05O12 type garnet (PVDF@LGLZNO) is coated directly on the LMO electrode and it functions as a promising artificial cathode–electrolyte interphase (CEI). The film thickness is optimized taking into account the electrospinning–processing time. To realize a cell with good capacity retention, excellent rate capability and resilience under harsher conditions (e.g. elevated temperature or high rates), the coated LMO cathode is coupled with a new anode which consists of sulfurized carbon derived from polyacrylonitrile (S-C(PAN)). The electrode (LMO-30 min) coated with the PVDF@LGLZNO composite material shows outstanding cycling stability and rate capability, as well as capacity retention when compared to the bare electrode both at room temperature (25 °C) and elevated temperature (55 °C). The PVDF@LGLZNO fibrous film coating suppresses the dissolution of manganese both at high C-rates and 55 °C, as supported by XPS, whereas PVDF coated and bare LMO cathodes are not able to prevent further deterioration of themselves. The film significantly minimizes undesirable side reactions at the cathode–electrolyte interface and reduces charge transfer resistance. The new cell with PVDF@LGLZNO (LMO-30 min) modified cathode and S-C(PAN) anode delivers capacity retention of 77% after 1000 cycles at 1C, corresponding to an average capacity decay of 0.023% per cycle.

Question: What's the cathode?
Answer: Lithium manganese oxide (LMO)
Lithium manganese oxide (LMO) is one of the most promising cathode materials for lithium-ion batteries. However, the dissolution of manganese and its deposition on the anode surface cause poor cycling stability. To alleviate these issues, a film composed of polyvinylidene difluoride (PVDF) and Li5.6Ga0.26La2.9Zr1.87Nb0.05O12 type garnet (PVDF@LGLZNO) is coated directly on the LMO electrode and it functions as a promising artificial cathode–electrolyte interphase (CEI). The film thickness is optimized taking into account the electrospinning–processing time. To realize a cell with good capacity retention, excellent rate capability and resilience under harsher conditions (e.g. elevated temperature or high rates), the coated LMO cathode is coupled with a new anode which consists of sulfurized carbon derived from polyacrylonitrile (S-C(PAN)). The electrode (LMO-30 min) coated with the PVDF@LGLZNO composite material shows outstanding cycling stability and rate capability, as well as capacity retention when compared to the bare electrode both at room temperature (25 °C) and elevated temperature (55 °C). The PVDF@LGLZNO fibrous film coating suppresses the dissolution of manganese both at high C-rates and 55 °C, as supported by XPS, whereas PVDF coated and bare LMO cathodes are not able to prevent further deterioration of themselves. The film significantly minimizes undesirable side reactions at the cathode–electrolyte interface and reduces charge transfer resistance. The new cell with PVDF@LGLZNO (LMO-30 min) modified cathode and S-C(PAN) anode delivers capacity retention of 77% after 1000 cycles at 1C, corresponding to an average capacity decay of 0.023% per cycle.

Question: What's the anode?
Answer:  S-C(PAN)
In view of the bifunctional catalytic performance of MoP@NiCo-LDH/NF-20 towards both UOR and HER, the material was used as both anode and cathode to form a two-electrode electrolyser (MoP@NiCo-LDH/NF-20‖MoP@NiCo-LDH/NF-20). Fig. 7a shows the LSV curves of electrolysis cell voltages for both water and water with urea. At 100 mA cm−2, urea–water electrolysis (UOR & HER) requires much less driving voltage (1.405 V) than pure water electrolysis (OER & HER) (1.697 V). The inset of Fig. 7a illustrates a histogram of the driving voltages required at 20, 40, 60, and 100 mA cm−2. It can be seen intuitively that the driving voltage required by urea auxiliary electrolysis is smaller than that required by pure water electrolysis no matter whether the current density is low or high. Fig. 7b shows the polarization curves of the MoP/NF‖MoP/NF, NiCo-LDH/NF‖NiCo-LDH/NF, MoP@NiCo-LDH/NF-20‖MoP@NiCo-LDH/NF-20, and Pt/C/NF‖IrO2/NF electrolysis cells in 1 M KOH with 0.5 M urea. At 100 mA cm−2, the cell voltages of MoP/NF‖MoP/NF, NiCo-LDH/NF‖NiCo-LDH/NF, MoP@NiCo-LDH/NF-20‖MoP@NiCo-LDH/NF-20, and Pt/C/NF‖IrO2/NF are 1.494, 1.579, 1.405, and 1.708 V, respectively (Table S1†). The results show that at the same current density, the driving cell voltage of MoP@NiCo-LDH/NF-20‖MoP@NiCo-LDH/NF-20 is the lowest among all four cells. The significant bifunctional catalytic activity of MoP@NiCo-LDH/NF-20 exceeds those of reported non-precious metal catalysts (Table S2†).

Question: What's the cathode?
Answer:  MoP@NiCo-LDH/NF-20
In view of the bifunctional catalytic performance of MoP@NiCo-LDH/NF-20 towards both UOR and HER, the material was used as both anode and cathode to form a two-electrode electrolyser (MoP@NiCo-LDH/NF-20‖MoP@NiCo-LDH/NF-20). Fig. 7a shows the LSV curves of electrolysis cell voltages for both water and water with urea. At 100 mA cm−2, urea–water electrolysis (UOR & HER) requires much less driving voltage (1.405 V) than pure water electrolysis (OER & HER) (1.697 V). The inset of Fig. 7a illustrates a histogram of the driving voltages required at 20, 40, 60, and 100 mA cm−2. It can be seen intuitively that the driving voltage required by urea auxiliary electrolysis is smaller than that required by pure water electrolysis no matter whether the current density is low or high. Fig. 7b shows the polarization curves of the MoP/NF‖MoP/NF, NiCo-LDH/NF‖NiCo-LDH/NF, MoP@NiCo-LDH/NF-20‖MoP@NiCo-LDH/NF-20, and Pt/C/NF‖IrO2/NF electrolysis cells in 1 M KOH with 0.5 M urea. At 100 mA cm−2, the cell voltages of MoP/NF‖MoP/NF, NiCo-LDH/NF‖NiCo-LDH/NF, MoP@NiCo-LDH/NF-20‖MoP@NiCo-LDH/NF-20, and Pt/C/NF‖IrO2/NF are 1.494, 1.579, 1.405, and 1.708 V, respectively (Table S1†). The results show that at the same current density, the driving cell voltage of MoP@NiCo-LDH/NF-20‖MoP@NiCo-LDH/NF-20 is the lowest among all four cells. The significant bifunctional catalytic activity of MoP@NiCo-LDH/NF-20 exceeds those of reported non-precious metal catalysts (Table S2†).

Question: What's the anode?
Answer:  MoP@NiCo-LDH/NF-20
Ni-rich layered cathode materials are at the forefront to be deployed in high energy density Li-ion batteries for the automotive market. However, the intrinsic poor structural and interfacial stability during overcharging could trigger violent thermal failure, which severely limits their wide application. To protect the Ni-rich cathode from overcharging, we firstly report a redox-active cation, thioether-substituted diaminocyclopropenium, as an electrolyte additive to limit the cell voltage within the safe value during overcharging. The organic cation demonstrates a record-breaking electrochemical reversibility at ∼4.55 V versus Li+/Li and solubility (0.5 M) in carbonate-based electrolyte. The protection capability of the additive was explored in two cell chemistries: a LiNi0.8Co0.15Al0.05O2/graphite cell and a LiNi0.8Co0.15Al0.05O2/silicon–graphene cell with areal capacities of ∼2.2 mA h cm−2 and ∼3 mA h cm−2, respectively. With 0.2 M addition, the LiNi0.8Co0.15Al0.05O2/graphite cell survived 54 cycles at 0.2C with 100% overcharge. Moreover, the cell can carry an utmost 4.4 mA cm−2 (2C) with 100% overcharge and a maximum capacity of 7540% SOC at 0.2C.

Question: What's the cathode?
Answer: Ni-rich layered
Ni-rich layered cathode materials are at the forefront to be deployed in high energy density Li-ion batteries for the automotive market. However, the intrinsic poor structural and interfacial stability during overcharging could trigger violent thermal failure, which severely limits their wide application. To protect the Ni-rich cathode from overcharging, we firstly report a redox-active cation, thioether-substituted diaminocyclopropenium, as an electrolyte additive to limit the cell voltage within the safe value during overcharging. The organic cation demonstrates a record-breaking electrochemical reversibility at ∼4.55 V versus Li+/Li and solubility (0.5 M) in carbonate-based electrolyte. The protection capability of the additive was explored in two cell chemistries: a LiNi0.8Co0.15Al0.05O2/graphite cell and a LiNi0.8Co0.15Al0.05O2/silicon–graphene cell with areal capacities of ∼2.2 mA h cm−2 and ∼3 mA h cm−2, respectively. With 0.2 M addition, the LiNi0.8Co0.15Al0.05O2/graphite cell survived 54 cycles at 0.2C with 100% overcharge. Moreover, the cell can carry an utmost 4.4 mA cm−2 (2C) with 100% overcharge and a maximum capacity of 7540% SOC at 0.2C.

Question: What's the cathode?
Answer: Ni-rich
The non-renewability of fossil energy and growing environmental pollution have spurred the development of sustainable energy technologies, such as fuel cells and metal–air batteries. Of these, zinc–air batteries represent a promising energy technology for next-generation portable electronics, due to their good rechargeability and high theoretical density (1370 W h kg−1), where the device performance is largely dictated by the reversible catalysts at the cathode for oxygen reduction (ORR) and oxygen evolution reactions (OER). Platinum-based nanoparticles have been the catalysts of choice for ORR, whereas Ir and Ru-based nanoparticles for OER. Yet their high costs and low natural abundance have hindered the practical applications of the technology. Thus, development of low-cost and high-performance electrocatalysts for ORR and OER have been attracting extensive interest. Recent reports have shown that atomically dispersed metals (such as Mn, Fe and Co) within nitrogen-doped carbons, exhibit excellent electrocatalytic performance towards ORR and may even surpass the corresponding nanoparticle counterparts. In both experimental and theoretical studies, Fe single atom catalysts (SACs) have been recognized as the most active catalysts towards ORR in alkaline media. Unfortunately, for the Fe-based SACs, Fenton reaction involving the Fe center and ORR byproduct H2O2 produces hydroxyl and oxygen radicals, which not only affect the durability of the catalysts by changing its chemical structure, but also damage the battery devices by corroding the ion membranes. Additionally, theoretical and experimental studies have shown that the Fe-based SACs performs poorly towards OER, as compared to other 3d transition metals, such as Co and Ni. Therefore, it is critical to improve the ORR durability and OER activity of Fe SACs such that they may be used as bifunctional oxygen catalysts in rechargeable Zn–air battery. Towards this end, the incorporation of Co atomic sites into Fe SACs represents a unique strategy. First of all, the weak Fenton activity between Co and H2O2 is anticipated to markedly enhance the ORR stability of Fe SACs. In addition, prior studies have shown that Co-doped carbon exhibits a low overpotential and small Tafel slope towards OER. Thus, it is envisioned that atomically dispersing Co atoms into Fe-doped carbon may achieve a bimetal catalyst with excellent ORR/OER activity and enhanced durability, in comparison to the monometal counterparts.

Question: What's the cathode?
Metal sulfides having various micro-/nanostructures and compositions (Fig. 2), such as spherical/non-spherical hollow materials, high surface area/porosity/selectivity structures, hierarchical carbon-based hybrids, and unique functional materials, have been successfully prepared in recent years through various synthetic approaches. These material systems offer the possibility to study the influence of these features on the electrochemical properties of Li–S batteries. Generally, there are two typical strategies to building metal sulfides and sulfur cathode composites: (i) one-step in situ fabrication and (ii) stepwise synthesis, which often involves injection of sulfur into a host via melt/solution-diffusion methods. Synthetic strategies involving the use of metal sulfides to protect Li anodes, modify separators, and engineer interlayers, are more flexible than those related to the use of metal sulfides and sulfur cathode composites, owing to the removal of the sulfur injection process. We consider the fundamental challenges facing Li–S batteries and discuss synthetic strategies to highlight their attractive features. Accordingly, the methods can be broadly categorized into five groups: (i) building buffer space to accommodate volume fluctuations; (ii) enhancing the binding ability for LiPSs; (iii) improving the electronic conductivity of the active material; (iv) increasing the sulfur loading; and (v) designing other specialized functions.

Question: What's the cathode?
Answer: sulfur
Metal sulfides having various micro-/nanostructures and compositions (Fig. 2), such as spherical/non-spherical hollow materials, high surface area/porosity/selectivity structures, hierarchical carbon-based hybrids, and unique functional materials, have been successfully prepared in recent years through various synthetic approaches. These material systems offer the possibility to study the influence of these features on the electrochemical properties of Li–S batteries. Generally, there are two typical strategies to building metal sulfides and sulfur cathode composites: (i) one-step in situ fabrication and (ii) stepwise synthesis, which often involves injection of sulfur into a host via melt/solution-diffusion methods. Synthetic strategies involving the use of metal sulfides to protect Li anodes, modify separators, and engineer interlayers, are more flexible than those related to the use of metal sulfides and sulfur cathode composites, owing to the removal of the sulfur injection process. We consider the fundamental challenges facing Li–S batteries and discuss synthetic strategies to highlight their attractive features. Accordingly, the methods can be broadly categorized into five groups: (i) building buffer space to accommodate volume fluctuations; (ii) enhancing the binding ability for LiPSs; (iii) improving the electronic conductivity of the active material; (iv) increasing the sulfur loading; and (v) designing other specialized functions.

Question: What's the anode?
Answer: Li
Based on the above theory, the self-charging process of the flexible SSCFB was illustrated as follows (Fig. 7). In the initial stage, the device suffers from no external strains/deformations and an electrochemical equilibrium state is present (Fig. 7a). In the second stage, external strains/deformations are applied on the device, and the piezoelectric gel-electrolyte in the device generates a piezoelectric field with a positive potential close to the cathode and negative potential around the anode (Fig. 7b). As a result, Na+ migration is carried out through the piezoelectric gel-electrolyte from the cathode to the anode, followed by a charging reaction in the device (cathode: Na3V2(PO4)3 → NaV2(PO4)3 + 2Na+ + 2e−; anode: xC + 2Na+ + 2e− → Na2Cx) (Fig. 7c). Impressively, when the external force is removed, the piezoelectric field doesn't disappear immediately, and the self-charging process can proceed by virtue of the internal residual strains (Fig. 7d). Once the piezoelectric potential is balanced by the re-distribution of Na+, a new equilibrium of the electrodes is formed (Fig. 7e). Finally, the piezoelectric field disappears along with the complete loss of residual strain, and a reverse migration of Na+ to the original position is conducted (Fig. 7f). Once the external force is applied on the device again, the self-charging process can be repeated.

Question: What's the cathode?
Answer: Na3V2(PO4)3
Based on the above theory, the self-charging process of the flexible SSCFB was illustrated as follows (Fig. 7). In the initial stage, the device suffers from no external strains/deformations and an electrochemical equilibrium state is present (Fig. 7a). In the second stage, external strains/deformations are applied on the device, and the piezoelectric gel-electrolyte in the device generates a piezoelectric field with a positive potential close to the cathode and negative potential around the anode (Fig. 7b). As a result, Na+ migration is carried out through the piezoelectric gel-electrolyte from the cathode to the anode, followed by a charging reaction in the device (cathode: Na3V2(PO4)3 → NaV2(PO4)3 + 2Na+ + 2e−; anode: xC + 2Na+ + 2e− → Na2Cx) (Fig. 7c). Impressively, when the external force is removed, the piezoelectric field doesn't disappear immediately, and the self-charging process can proceed by virtue of the internal residual strains (Fig. 7d). Once the piezoelectric potential is balanced by the re-distribution of Na+, a new equilibrium of the electrodes is formed (Fig. 7e). Finally, the piezoelectric field disappears along with the complete loss of residual strain, and a reverse migration of Na+ to the original position is conducted (Fig. 7f). Once the external force is applied on the device again, the self-charging process can be repeated.

Question: What's the anode?
Answer: C
A superfast and stable ssZIB based on a CNF–PAM hydrogel electrolyte and a Mg0.23V2O5·1.0H2O cathode was successfully developed from this work. The designed CNF–PAM hydrogel shows high stretchability and robust mechanical stability. Moreover, the porous CNF–PAM hydrogel electrolyte provides efficient pathways for the transportation of zinc ions. And the robust layered structure of V2O5·1.0H2O pillared with Mg2+ ions and water supports the fast insertion/extraction of zinc ions in the lattice. The prepared ssZIB shows remarkably high rate capability and long-term cycling performance. At a high current density of 5 A g−1, the ssZIB provides a high specific capacity of about 216 mA h g−1 within a charging time of only three minutes for over 2000 cycles, maintaining 98.6% of the initial capacity. Furthermore, with the designed CNF–PAM hydrogel electrolyte, a spring ssZIB was also obtained. The spring ssZIB is still working under repeated stretching. Even under some critical states, such as repeated bending, freezing, and heating, the ssZIB shows high stability and reliability. The ssZIB shows extraordinary electrochemical performance, robust stability, and high stretchability, which helps bring new opportunities for using ZIBs in practical large-scale storage devices.

Question: What's the cathode?
Answer: Mg0.23V2O5·1.0H2O
A superfast and stable ssZIB based on a CNF–PAM hydrogel electrolyte and a Mg0.23V2O5·1.0H2O cathode was successfully developed from this work. The designed CNF–PAM hydrogel shows high stretchability and robust mechanical stability. Moreover, the porous CNF–PAM hydrogel electrolyte provides efficient pathways for the transportation of zinc ions. And the robust layered structure of V2O5·1.0H2O pillared with Mg2+ ions and water supports the fast insertion/extraction of zinc ions in the lattice. The prepared ssZIB shows remarkably high rate capability and long-term cycling performance. At a high current density of 5 A g−1, the ssZIB provides a high specific capacity of about 216 mA h g−1 within a charging time of only three minutes for over 2000 cycles, maintaining 98.6% of the initial capacity. Furthermore, with the designed CNF–PAM hydrogel electrolyte, a spring ssZIB was also obtained. The spring ssZIB is still working under repeated stretching. Even under some critical states, such as repeated bending, freezing, and heating, the ssZIB shows high stability and reliability. The ssZIB shows extraordinary electrochemical performance, robust stability, and high stretchability, which helps bring new opportunities for using ZIBs in practical large-scale storage devices.

Question: What's the electrolyte?
Answer: CNF–PAM hydrogel
Several routes can be envisaged to improve the mechanical response of the composite cathode, none of which is likely to be very easy. This includes the optimization of cathode morphology, cathode chemistry/structure, mechanical properties of the solid electrolyte, and use of external pressure. Reducing the cathode surface displacement is critical for lowering the mechanical strain during cycling, which can be achieved by decreasing the cathode particle size or cathode strain. For a cathode material with a specific strain, a smaller particle size would result in less surface displacement and therefore reduced stress at the cathode/solid electrolyte interface. However, reducing the cathode particle size could negatively affect the cathode utilization and energy density of SSBs. Reducing the cathode strain during cycling is another way to minimize mechanical issues. Different cathode chemistries and structures have been shown to lead to different volume change during cycling. The current results motivate the search for high-energy-density electrode materials with small volume change or “zero-strain”. Different solid-electrolyte materials will also result in different mechanical degradation behavior. For example, the rapid development of cracks in the first few cycles was observed in SSBs with an oxide-based solid electrolyte, which is more rigid than the sulfide solid electrolyte used in the current study. In contrast, polymer-based composite solid electrolytes can accommodate larger strain and have been shown to improve the cycling stability. Therefore, developing a solid electrolyte with higher elasticity is an additional route to mitigate mechanical instability. Finally, applying a large external pressure (stack pressure) during cycling could in principle reduce the contact loss at the cathode/solid electrolyte interface, but such a large stack pressure may not be practical for large format cells.

Question: What's the cathode?