Advances of Zn Metal-Free "Rocking-Chair"-Type Zinc Ion Batteries: Recent Developments and Future Perspectives.

Aqueous zinc ion battery (AZIBs) has attracted the attention of many researchers because of its safety, economy, environmental protection, and high ionic conductivity of electrolytes. However, the battery greatly suffers from zinc dendrite produced by zinc metal anode leading to poor cycle life and even unsafe problems, which limit its further development for various important applications. It is known that the success of the commercialization of lithium-ion batteries (LIBs) is mainly due to replacement of lithium metal anode with graphite, which avoids the formation of Li dendrite. Therefore, it is an important step to develop aqueous zinc ion anode to replace conventional zinc metal one with zinc-metal free anode material. In this review, the working principle and development prospect of "rocking-chair" AZIBs are introduced. The research progress of different types of zinc metal-free anode materials and cathode materials in "rocking-chair" AZIBs is reviewed. Finally, the limitations and challenges of the Zn metal-free "rocking-chair" AZIBs as well as solutions are deeply discussed, aiming to provide new strategies for the development of advanced zinc-ion batteries.

Series of Halogen Engineered Ni(OH)2 Nanosheet for Pseudocapacitive Energy Storage with High Energy Density.

Ni(OH)2 nanosheet, acting as a potential active material for supercapacitors, commonly suffers from sluggish reaction kinetics and low intrinsic conductivity, which results in suboptimal energy density and long cycle life. Herein, a convenient electrochemical halogen functionalization strategy is applied for the preparation of mono/bihalogen engineered Ni(OH)2 electrode materials. The theoretical calculations and experimental results found that thanks to the extraordinarily high electronegativity, optimal reversibility, electronic conductivity, and reaction kinetics could be achieved through F functionalization . However, benefiting from the largest ionic radius, INi(OH)2 contributes the best specific capacity and morphology transformation, which is a new finding that distinguishes it from previous reports in the literature. The exploration of the interaction effect of halogens (F, INi(OH)2 , F, BrNi(OH)2 , and Cl, INi(OH)2 ) manifests that F, INi(OH)2 delivers a higher specific capacity of 200.6 mAh g-1 and an excellent rate capability of 58.2% due to the weaker electrostatic repulsion, abundant defect structure, and large layer spacing. Moreover, the F, INi(OH)2 //FeOOH@NrGO device achieves a high energy density of 97.4 Wh kg-1 and an extremely high power density of 32426.7 W kg-1 , as well as good cycling stability. This work develops a pioneering tactic for designing energy storage materials to meet various demands.

Doping-driven electronic structure and conductivity modification of nickel sulfide.

The lack of electrical conductivity limits the electrochemical kinetic rate of the electrode material, resulting in the inability to reach its theoretical capacity. A facile method is adopted to improve the intrinsic conductivity of binary NiS2/Ni3S4 hybrid nickel sulfide, with the doping of transition metal atoms Co, Mn and Ag. Through the introduction of heteroatoms, the electronic structure of the electrode material is modified and the electrical conductivity is significantly improved, thus enhancing its electrochemical performance. The improvement of conductivity is attributed to the formation of intermediate bands of transition metals and the redistribution of electrons, and the result is demonstrated by experimental and density functional theory (DFT) calculations. As a result, the NiS2/Ni3S4 hybrid nickel sulfide after 0.5% amount of Co-doping reaches the highest specific capacitance of 2874 F g-1 at 1 A g-1, increasing specific capacitance of 653 F g-1 as 29.4% of the specific capacitance of non-doped nickel sulfide. The Co doped nickel sulfide also exhibits remarkable cycling stability compared with non-doped nickel sulfide. The assembled 2% Co-doped nickel sulfide//rGO, 0.5% Mn-doped nickel sulfide//rGO and 0.5% Ag-doped nickel sulfide//rGO asymmetric supercapacitors show a specific energy density of 36.6, 36.1 and 36.0 W h kg-1 at a power density of 800 W kg-1. This study provides a useful insight into the fabrication of high performance pseudocapacitive materials.

Clinical efficacy and prognosis of standard large trauma craniotomy for patients with severe frontotemporal craniocerebral injury.

OBJECTIVE: To observe the clinical efficacy, incidence of postoperative complications, and the quality of life in patients with severe craniocerebral injury undergoing standard large trauma craniotomy. METHODS: Seventy-eight patients with severe craniocerebral injury who had been admitted to Hubei Hanchuan People's Hospital were selected retrospectively and assigned into an observation group and control group according to the treatment received, with 39 patients in each group. Patients in the control group were treated with conventional decompressive craniotomy and those in the observation group with standard large trauma craniotomy. The prognosis (GOS score), intracranial pressure before and after surgery, neurological functions (NIHSS score), cerebral hemodynamics (Vm, Vs, PI), quality of life (SF-36 score) and postoperative complications were compared. RESULTS: The number of patients whose GOS scores were graded 5 was markedly higher in the observation group than that in the control group (P<0.05). The postoperative intracranial pressure and NIHSS scores in the observation group were lower than those in the control group (P<0.001). The postoperative Vm, Vs and PI were lower in the observation group than those in the control group, respectively (P<0.001). There was no statistical difference in the incidence of complications in the two groups (P>0.05). The SF-36 scores in the observation group were higher than those of the control group (P<0.01). CONCLUSION: Standard large trauma craniotomy is effective in treating patients with severe frontotemporal craniocerebral injury. It decreases intracranial pressure, improves neurological function and quality of life and results in a good prognosis.

Coordination agent-dominated phase control of nickel sulfide for high-performance hybrid supercapacitor.

The property of an active material is not only influenced by its morphology and size, but also by its crystal phase. The present phase regulation of nickel sulfide is mainly achieved by controlling the participation of sulfur source in reaction. Thus, new perspectives direct at phase control need to be explored and supplemented. Herein, we proposed a novel coordination agent-dominated phase modulation strategy assisted by a hydrothermal process. It is found that increasing the amount of coordination agent can drove the phase transformation from the initial composite of ß-NiS/α-NiS/Ni3S4 to ß-NiS/α-NiS, and then to pure ß-NiS. The mechanism of phase regulation has been proposed, and the general application of this method has been demonstrated. By employing coordination agent, the size of resulted products is reduced, and the morphology is optimized. As a result, all of the pure ß-NiS electrodes indicate significantly enhanced specific capacity than the pristine ß-NiS/α-NiS/Ni3S4 composite. Notably, the sample synthesized with 3 mmol of urea (S11) shows uniform morphology and smallest size, and it gives a highest specific capacity of 223.8 mAh g-1 at 1 A g-1, almost 1.5 times of the original sample. The fabricated S11//rGO device delivers a high energy density of 56.6 Wh·kg-1 at a power density of 407.5 W·kg-1, and keeps an impressive capacity retention of 84% after 20,000 cycles. This work put forwards a new prospect for controlling the phase and composition of nickel sulfide based on coordination chemistry.

Template-free synthesis of ß-NiS ball-in-ball microspheres for a high-performance asymmetrical supercapacitor.

While significant advances have been made in the synthesis of core-/multi-shell materials, the synthetic process usually involves a soft/hard template and complicated procedures. In particular, it is extremely difficult to fabricate single-component core-shell structures for nickel sulfides (NSs) with a controlled phase. In this work, we demonstrate a novel facile method to synthesize a single-component ß-NiS ball-in-ball microsphere. The ball-in-ball structure is easily obtained by uniquely employing 2-mercaptopropionic acid (2-MPA) as the sulfur source and ethanol as the solvent based on the Ostwald ripening process. In particular, our work demonstrates that the chemical structure of sulfur sources and solvents plays a key role in the formation of the pure ß-NiS ball-in-ball structure. When used as an electrode active material, the ß-NiS ball-in-ball microspheres exhibit two times stronger specific capacity and three times higher rate performance than NSs produced by a hydrothermal method. The fabricated NS-2//rGO asymmetrical supercapacitor (ASC) displays an energy density of 46.4 W h kg-1 at a power density of 799.0 W kg-1 and good cycling performance. Thus, this study provides a new method for controlling the phase and morphology of NSs.

Selenium Defect Boosted Electrochemical Performance of Binder-Free VSe2 Nanosheets for Aqueous Zinc-Ion Batteries.

As a typical transition-metal dichalcogenides, vanadium diselenide (VSe2) is a promising electrode material for aqueous zinc-ion batteries due to its metallic characteristics and excellent electronic conductivity. In this work, we propose a strategy of hydrothermal reduction synthesis of stainless-steel (SS)-supported VSe2 nanosheets with defect (VSe2-x-SS), thereby further improving the conductivity and activity of VSe2-x-SS. Density functional theory calculations confirmed that Se defect can adjust the adsorption energy of Zn2+ ions. This means that the adsorption/desorption process of Zn2+ ions on VSe2-x-SS is more reversible than that on pure SS-supported VSe2 (VSe2-SS). As a result, the Zn//VSe2-x-SS battery showed more excellent electrochemical performance than Zn//VSe2-SS. The VSe2-x-SS electrode shows a good specific capacity of 265.2 mA h g-1 (0.2 A g-1 after 150 cycles), satisfactory rate performance, and impressive cyclic stability. In addition, we also have explored the energy-storage mechanism of Zn2+ ions in this VSe2-x-SS electrode material. This study provides an effective strategy for the rational design of electrode materials for electrochemical energy-storage devices.

Application value and feasibility analysis of humanistic health management for cancer screening in physical examination.

OBJECTIVE: To investigate the application value and feasibility of humanistic health management in cancer screening in physical examination. METHODS: A total of 100 carcinoma patients were randomly grouped into the control group and the experimental group, with 50 cases in each group. The patients in the control group received a general physical examination, while those in the experimental group received humanistic health care management model, health education, environmental management, private nursing and emergency management. The two groups were compared in missing item rate, health knowledge score, physical examination quality, basic literacy of nursing staff, adverse events and physical examination satisfaction. RESULTS: There was 1 case of missing items in the ENT (ear nose throat branch) in the experimental group, with a missing item rate of 2.00%, and 7 cases of missing items in the control group, with a missing item rate of 14.00% (χ2=9.000, P=0.003). The score of mastering health knowledge in the experimental group was higher than that in the control group (t=15.663, P<0.001). Compared with the control group, the experimental group experienced shorter time of physical examination and obtained higher reliability and efficiency of physical examination (all P<0.05) and higher scores of professional ethics, interpersonal communication, coordination ability, humanistic quality and civility of nursing staff (all P<0.05). In addition, the incidence of adverse events in the control group was 32.00% (16/50), which was higher than that in the experimental group (18.00%, 9/50; χ2=3.920, P=0.048). There was no difference in satisfaction between the two groups (P>0.05). CONCLUSION: Humanistic health management can improve the efficiency of medical examination, the mastery of health knowledge and reduce the rate of missed examinations and adverse accidents, thus improving the overall satisfaction of patients.

Experimental and Theoretical Investigation of the Effect of Oxygen Vacancies on the Electronic Structure and Pseudocapacitance of MnO2.

Defect engineering is an effective way to modulate the intrinsic physicochemical properties of materials. In this work, δ-MnO2 with oxygen vacancies is fabricated by a simple oxidation or reduction process, and the relationship between the electronic structure and pseudocapacitance is systematically studied through experimental analysis and theoretical calculations. The peaks in the Raman spectra of the as-prepared samples are shifted compared with those of pure MnO2 and the Mn3+ /Mn4+ ratio and O species content also change after the introduction of oxygen vacancies. The optimized samples exhibit a better specific capacitance of 207 F g-1 after the oxidation process and 181.4 F g-1 after the reduction treatment compared with only 143.9 F g-1 for the pure MnO2 . The samples obtained through the oxidation or reduction process also retain 93.3 or 86.4 % of the initial capacity after 5000 cycles. The excellent properties are attributed to the enhanced conductivity and increased surface reactivity or electrochemically active sites. Theoretical calculations demonstrate that the presence of oxygen vacancies leads to an increase in the density of states, which improves the redox reaction of MnO2 . This study will provide a reference for exploring and designing highperformance pseudocapacitive materials.

Waste bones derived nitrogen-doped carbon with high micropore ratio towards supercapacitor applications.

Fabrication of high-performance electrodes from waste biomass has attracted increasing attention among the energy storage and conversion field. In this work, we have synthesized nitrogen-doped activated carbon by a simultaneous pyrolysis/activation method from waste bones. It is found that the specific surface area and pore structure of as-synthesized carbon depends on the carbonization temperature (500-800 °C), and the highest specific surface area is 1522 m2 g-1. The electrochemical properties of Pork bone, Blackfish bone, Eel bone based activated carbon (PBAC, BFAC, EBAC) mainly depend on their micro-/mesoporosity. Three samples PBAC-600, BFAC-600 and EBAC-600, which have higher ratio of micropore surface area and nitrogen content, exhibit enhanced specific capacitance of 263, 302 and 264F g-1 in 6 M KOH electrolyte. Furthermore, the assembled symmetric supercapacitors of PBAC-600 can deliver energy density as high as 7.0 and 26.2 Wh Kg-1 in the aqueous and ionic liquid electrolyte, respectively. Such excellent performance can be attributed to the microporous structure, reasonable pore size distribution and nitrogen self-doping of the activated carbon. This research indicates that waste bones have great potential for mass fabrication of the activated carbon electrodes for energy storage applications.

[Evaluation of chemomechanical and traditional mechanical caries removal in indirect pulp capping of symmetric primary molars].

OBJECTIVE: To evaluate the difference between chemomechanical and traditional mechanical caries removal in indirect pulp capping of the symmetric primary molars. METHODS: A total of 192 children with deep caries in the two symmetric primary molars were studied. The two symmetric primary molars were divided into two groups for treatment with chemomechanical method with Carisolv(TM) system or traditional mechanical method. After caries removal, calcium hydroxide agent was placed as the protective base, and glass ionomer cement was used to restore the teeth. The patients were followed up every 1 month within one year after the operation. RESULTS: The percentage of healthy primary molar pulp was 95.3% with chemomechanical method and 87.0% with traditional method, showing a significant difference between the two methods. CONCLUSION: Chemomechanical caries removal is more effective in preserving the healthy pulp than the traditional method.

[A three-dimensional finite element analysis of stress distribution in mandibular FPDs with different length pontics].

OBJECTIVE: To investigate the stress distribution in the mandibular fixed partial denture (FPD) by changing the length of pontics. METHODS: Based on a 3-DFE model of the mandibular FPD, we analyzed the stress distribution in the mandibular FPDs by loading the same level force at pontics with different lengths that were 2 to 4 times of normal length. RESULTS: The distribution trends of the stresses in the mandibular FPDs with differently elongated pontics were similar, but the highest von Mises stress in the bridge was enlarged. CONCLUSION: Damages may develop in the mandibular FDP, when the length of the pontic is longer than 3 times of normal length.