Dual‐ion batteries (DIBs) have attracted much attention due to their advantages of low cost and especially environmental friendliness. However, the capacities of most DIBs are still unsatisfied (≈100 ...mAh g−1) ascribed to the limited capacity of anions intercalation for conventional graphite cathode. In this study, 3D porous microcrystalline carbon (3D‐PMC) was designed and synthesized via a self‐templated growth approach, and when used as cathode for a DIB, it allows both intercalation and adsorption of anions. The microcrystalline carbon is beneficial to obtain capacity originated from anions intercalation, and the 3D porous structure with a certain surface area contributes to anions adsorption capacity. With the synergistic effect, this 3D‐PMC is utilized as cathode and tin as anode for a sodium‐based DIB, which has a high capacity of 168.0 mAh g−1 at 0.3 A g−1, among the best values of reported DIBs so far. This cell also exhibits long‐term cycling stability with a capacity retention of ≈70% after 2000 cycles at a high current rate of 1 A g−1. It is believed that this work will provide a strategy to develop high‐performance cathode materials for DIBs.
3D porous microcrystalline carbon is designed and synthesized via a self‐templated growth approach. The microcrystalline carbon is beneficial to obtain capacity originated from anions intercalation, and the 3D porous structure with a certain surface area contributes to anions adsorption capacity. After it is used as the cathode for a sodium‐based dual‐ion battery, high capacity and long‐term cycling stability are achieved.
Sodium‐based dual ion batteries (SDIBs) have garnered significant attention as novel energy storage devices offering the advantages of high‐voltage and low‐cost. Nonetheless, conventional ...electrolytes exhibit low resistance to oxidation and poor compatibility with electrode materials, resulting in rapid battery failure. In this study, for the first time, a chlorination design of electrolytes for SDIB, is proposed. Using ethyl methyl carbonate (EMC) as a representative, chlorine (Cl)‐substituted EMC not only demonstrates increased oxidative stability ascribed to the electron‐withdrawing characteristics of chlorine atom, electrolyte compatibility with both the cathode and anode is also greatly improved by forming Cl‐containing interface layers. Consequently, a discharge capacity of 104.6 mAh g−1 within a voltage range of 3.0–5.0 V is achieved for Na||graphite SDIB that employs a high graphite cathode mass loading of 5.0 mg cm−2, along with almost no capacity decay after 900 cycles. Notably, the Na||graphite SDIB can be revived for an additional 900 cycles through the replacement of a fresh Na anode. As the mass loading of graphite cathode increased to 10 mg cm−2, Na||graphite SDIB is still capable of sustaining over 700 times with ≈100% capacity retention. These results mark the best outcome among reported SDIBs. This study corroborates the effectiveness of chlorination design in developing high‐voltage electrolytes and attaining enduring cycle stability of Na‐based energy storage devices.
Chlorination design strategy is proposed for sodium‐based dual ion batteries, and as a proof‐of‐concept, the chlorinated electrolyte based on chloromethyl ethyl carbonate displays notably enhanced oxidative stability and highly reversible anion intercalation into the graphite cathode; meanwhile, the uniform and efficient plating/stripping of Na+ ions on the anode is also achieved.
Sodium‐ion capacitors (SICs) have attracted enormous attention due to their high energy density and high power density. In this work, N and S codoped hollow carbon nanobelts (N/S‐HCNs) are ...synthesized by a self‐templated method. The as‐synthesized carbon nanobelts exhibit excellent performance in pseudocapacitance and electric double layer anions adsorption. After pairing the N/S‐HCNs cathode with a tin foil anode in a carbonate electrolyte, the obtained SIC achieves a high specific capacity of 400 mAh g−1 at 1 A g−1 (based on the mass of cathode material) and energy density of 250.35 Wh kg−1 at 676 W kg−1 (based on the total mass of cathode and anode materials). Besides, the presented SIC also demonstrates high cycling stability with almost 100% capacity retention after 10 000 cycles, which is among the best results of the reported SICs, suggesting the potential for high‐performance energy storage applications.
A sodium ion capacitor composed of a N and S codoped hollow carbon nanobelts cathode and tin anode delivers a high specific capacity of 400 mAh g−1 at 1 A g−1 and an energy density of 250.35 Wh kg−1 at 676 W kg−1, and demonstrates extraordinary long cycling stability with almost 100% capacity retention even after 10 000 cycles.
Potassium-ion batteries are promising candidates for large-scale energy storage applications owing to their merits of abundant resources, low cost, and high working voltage. However, the unsatisfying ...rate performance and cycling stability caused by sluggish K+ diffusion kinetics and dramatic volume expansion hinder the development of potassium-ion batteries. In this study, we design a flexible potassium-ion hybrid capacitor (PIHC) by combining the K-Sn alloying mechanism on the Sn anode and the fast capacitive behavior on the AC cathode with high surface area and mesoporous structure. After optimization, the fabricated Sn||AC PIHC achieves both a high energy density of 120 W h kg–1 and high power density of 2850 W kg–1, much better than other similar hybrid devices. Moreover, a gel polymer electrolyte with a 3D porous structure and high ionic conductivity was employed to improve the structural stability of the Sn anode, which not only realizes good flexibility but also achieves long cycling stability with a capacity retention of nearly 100% for 2000 cycles at a high current density of 3.0 A g–1.
For electronic applications, graphene prepared by chemical vapor deposition (CVD) are required to be detached from the catalytic substrate, while retaining structural integrity. We demonstrate that ...CVD grown graphene on copper can be fully decoupled from the substrate by immersion in water, without significant damage to graphene. We find that the decoupling starts from the graphene edges and defect sites, assisted by interfacial copper oxidation and water intercalation due to galvanic corrosion. Kinetics study reveals the activation energy of 0.3 ± 0.08 eV for this decoupling process, and interfacial oxidation acts as the dominating role. This facile water-immersion method can be extended to adjust the interaction between graphene and metals, and assist our understanding of interfacial chemistry in confined space.
Here, we present a one-step hydrogen reduction synthesis of Ni 3 S 2 nanoplatelets on graphene surface by using NiSO 4 ·3N 2 H 4 /GO as precursor. In this process, we have demonstrated that hydrazine ...molecule, which can coordinate with NiSO 4 in the form of pink precipitation, not only contributes to the formation of Ni 3 S 2 nanoplatelets structure, but also enhances the efficiency of SO 4 2− to S 2 4− conversion compared with NiSO 4 /GO. Supercapacitors made from the obtained Ni 3 S 2 /rGO composite exhibits a specific capacitance of 912.2 F g −1 at 2 mV s −1 scanning rate, and 875.6 F g −1 at galvanostatic discharge current density of 1 A g −1 , along with exceptional rate capability of 83.2% at discharge current density from 1 A g −1 to 10 A g −1 as well as good cycling stability. We attribute the excellent performance from the improved contact between graphene and the planar Ni 3 S 2 structure, which strengthens the synergistic effect with graphene as conductive support and Ni 3 S 2 nanoplatelets as the pseudocapacitive materials. This method allows the direct and efficient preparation of Ni 3 S 2 , and provides a simple route to integrate them with graphene for energy storage applications.
Dual‐ion batteries (DIBs) show the advantages of high working voltage, cost‐effectiveness, and environmental friendliness, but conventional electrolytes commonly cannot satisfy simultaneously the ...requirements of wide voltage range and high‐concentration, leading to poor cycling durability and limited energy density. In this work, an electrolyte system with 4.0 m lithium bis(fluorosulfonyl)imide (LiFSI) dissolved in tetramethylene sulfone, which shows merits of i) high oxidation potential ≈6.0 V to enable the insertion/deinsertion of FSI− reversibly at the graphite cathode, ii) dramatically suppressed gas formation under high working voltage, and iii) significantly elevated full‐cell DIB energy density, is developed. The DIB constructed with such an electrolyte is able to exhibit 113.3 mAh g−1 capacity and ≈4.6 V medium discharge voltage at 200 mA g−1, along with 94.7% capacity retention after 1000 cycles. Moreover, this DIB delivers an energy density of ≈180 Wh kg−1 (including electrolyte which contributes to the capacity and electrode materials), one of the best performances amongst the related work on DIBs.
The developed 4.0 m LiFSI/tetramethylene sulfone high‐concentration and high‐voltage electrolyte, significantly suppresses gas formation, enhances anion intercalation performance of FSI− at the graphite cathode, and enables reversible plating/stripping of Li+. As a result, the dual‐ion battery based on this electrolyte system is able to exhibit much improved capacity and energy density.
For lithium–sulfur batteries (LSBs), the dissolution of lithium polysulfide and the consequent “shuttle effect” remain major obstacles for their practical applications. In this study, we designed a ...new cathode material comprising MoSe2/graphene to selectively adsorb polysulfides on the selenium edges and thus to mitigate their dissolution. More specifically, few-layered MoSe2 was first grown on nitrogen-doped reduced graphene oxide (N-rGO) using the chemical vapor deposition method and then infiltrated with sulfur as the cathode for LSBs. An initial capacity of 1028 mA h g–1 was achieved for S/MoSe2/N-rGO at 0.2 C, higher than 981 and 405.1 mA h g–1 for pure graphene and sulfur, respectively, along with enhanced cycling durability and rate capability. Moreover, the density functional theory simulation, in addition to the experimental adsorption test, X-ray photoelectron spectroscopy analysis, and transmission electron microscopy technique, reveals the dual roles that MoSe2 plays in improving the performance of LSBs by functioning as the binding sites for lithium polysulfides and as the platform that enables fast Li-ion diffusion by reducing its diffusion barrier. The reported finding suggests that the transition-metal selenides could be an efficient alternative material as the cathode for LSBs.
Sodium (Na) ion‐based dual‐ion batteries (Na‐DIBs) have attracted great attention, owing to their benefits of low cost, high working voltage, and environmental friendliness. However, the limited ...capacity and low tap density of currently reported anode materials restrict the further improvement of Na‐DIBs. Herein, a micro–nano structure with vertically aligned WSe2 nanoflakes anchored tightly on a micron‐sized carbon sphere (WSe2/CS) is successfully constructed via combining the molecular coupling and self‐assembly strategy. Within this hierarchical structure, the WSe2 nanoflakes can shorten the diffusion path for Na+ ions and alleviate structural deformation during the charge/discharge process; meanwhile, the micron‐sized carbon core provides conductive support and helps improve the total tap density of the anode electrode. As a result, this micron‐sized WSe2/CS displays a high specific capacity of ≈252.8 mAh g−1 and good cycling performance with ≈92% capacity retention after 1200 cycles. Moreover, by pairing this WSe2/CS anode with environmental friendly graphite as cathode, a proof‐of‐concept Na‐DIB shows 85.6% capacity retention after 1000 cycles, which is among the best performances of previously reported Na‐DIBs.
Through molecular coupling and self‐assembly strategy, a micro–nano structure with vertically aligned WSe2 nanoflakes anchored tightly on a micron‐sized carbon sphere is successfully constructed. This hierarchical structure not only shows enhanced cycling stability and reaction kinetics for Na+ storage, but meanwhile also helps improve the tap density of the anode electrode.
K-based dual-ion batteries (K-DIBs) show the advantages of being cost-effective, high-voltage, and environmentally friendly; however, their energy density is restricted by limited intercalation ...capacity of anions at the graphite cathode and low electrolyte concentration. Herein, we developed a highly concentrated electrolyte system by dissolving 6.6 m potassium bis(fluorosulfonyl)imide (KFSI) into nonflammable trimethyl phosphate (TMP). Advantages exhibited by this concentrated KFSI/TMP electrolyte include (1) high oxidation potential (over 5.4 V) that improves the intercalation reversibility and capacity of FSI– anions at the graphite cathode side; (2) enhanced cycling performance of tin (Sn) foil anode; and (3) remarkably improved energy density of K-DIBs. With the concentrated electrolyte system, a proof-of-concept K-DIB constructed with a graphite cathode and a Sn foil anode displays a high specific discharge capacity of 93.6 mA h g–1 at 300 mA g–1 and energy density of ∼144 W h kg–1 (including electrode active materials and electrolytes), which are among the best results compared with previously reported K-DIBs.
