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Electrolytic MnO2/Zn batteries have attracted extensive attention for use in large-scale energy storage applications due to their low cost, high output voltage, safety, and environmental friendliness. However, the poor electrical conductivity of MnO2 limits its deposition and dissolution at large capacities, which leads to sluggish reaction kinetics and drastic capacity decay. Here, we report a theory-guided design principle for an electrolytic MnO2/Zn battery co-regulated with transition metal ions that has improved electrochemical performance in terms of deposition and stripping chemistries. We start with first-principles calculations to predict the electrolytic effects of regulating transition metal ions in the deposition/stripping chemistry of the MnO2 cathode. The results indicate that with the simultaneous incorporation of strongly electronegative Co and Ni, the MnO2 cathode tends to possess more active electron states, faster charge-transfer kinetics, and better electrical conductivity than either MnO2 regulated with Co or Ni on their own, or pristine MnO2; hence, this co-regulation is beneficial for the cathode solid/liquid MnO2/Mn2+ reactions. We then fabricate and demonstrate a novel Co2+ and Ni2+ co-regulated MnO2/Zn (Co-Ni-MnO2/Zn) battery that yields significantly better electrochemical performance, finding that the synergistic regulation of Co and Ni on MnO2 can significantly increase its intrinsic conductivity and achieve high rates and Coulombic efficiencies at large capacities. The aqueous Co-Ni-MnO2/Zn battery exhibits a high rate (10 C, 100 mA cm–2), high Coulombic efficiency (91.89%), and excellent cycling stability (600 cycles without decay) at a large areal capacity of 10 mAh cm–2. Our proposed strategy of co-regulation with transition metal ions offers a versatile approach for improving the electrochemical performance of aqueous electrolytic MnO2/Zn batteries in large-scale energy storage applications.

Separation and recovery of high-purity Si powder from kerf-loss Si slurry waste is a critical challenge for the photovoltaic industry. A green surfactant poly (propylene glycol) bis (2-aminopropyl ether) (PEA) was employed as a collector to facilitate the separation of Si and SiC from kerf-loss Si waste during flotation process. Single flotation tests of Si and SiC were conducted using 5 × 10−6 mol/L PEA, respectively. The separation efficiencies of Si and SiC in conjunction with PEA adsorption mechanism were investigated. It was found that the maximum recoveries rate of SiC and Si were 90.59% (pH 9.00) and 80.93% (pH 1.96), respectively. Furthermore, the maximum Si grade was determined as 92.31% at pH 8.95 for the sinking part of the mixture generating excellent floatability and selectivity. Zeta potential measurements, FT-IR spectra, and XPS analyses demonstrated that PEA was present on the surface of Si and SiC through electrostatic and hydrogen-bond interactions. The adsorption mechanism was explained based on the results. This research provides an efficient and environmentally friendly route for the separation and recovery of high purity silicon from kerf-loss Si waste.

Previous neuroimaging has paid little attention to the differences in brain network integration between patients with treatment-resistant depression(TRD) and non-TRD (nTRD), and the relationship between their impaired brain network integration and clinical symptoms has not been elucidated.Eighty one major depressive disorder (MDD) patients (40 in TRD, 41 in nTRD) and 40 healthy controls (HCs) were enrolled for the functional magnetic resonance imaging (fMRI) scans. A seed-based functional connectivity (FC) method was used to investigate the brain network abnormalities of default mode network (DMN), affective network (AN), salience network (SN) and cognitive control network (CCN) for the MDD. Finally, the correlation was analyzed between the abnormal FCs and 17-item Hamilton Rating Scale for Depression scale (HAMD-17) scores.Compared with the HC group, the FCs in DMN, AN, SN, CCN were altered in both the TRD and nTRD groups. Compared with the nTRD group, FC alterations in the AN and CCN were more abnormal in the TRD group, and the FC alterations were generally decreased at the SN in the TRD group. In addition, the FC values of right dorsolateral prefrontal cortices and left caudate nucleus in the TRD group and the FC values of right subgenual anterior cingulate cortex and left middle temporal gyrus in the nTRD group were positively correlated with HAMD-17 scale scores.Abnormal FCs are present in four brain networks (DMN, AN, SN, CCN) in both the TRD and nTRD groups. Except of DMN, FCs in AN, SN and CCN maybe underlay the neurobiological mechanism in differentiating TRD from nTRD.

Major depressive disorder is associated with a reward deficit manifested by abnormal striatal function. However, differences between treatment-resistant depression (TRD) and non TRD (nTRD) in striatal whole-brain functional connectivity (FC) have not been elucidated. Thirty-eight patients with TRD, 42 patients with nTRD, and 39 healthy controls (HCs) were recruited for this study. A seed-based FC approach was used to analyze abnormalities in six predefined striatal subregion circuits in the three groups of subjects, and further explore the correlation between abnormal FC and clinical symptoms. Results revealed that compared with the nTRD group, the TRD group showed increased FC of the inferior ventral striatum with the bilateral orbital area of the middle frontal gyrus, right cerebellum posterior lobe, left parahippocampal gyrus, left middle occipital gyrus and left lingual gyrus. Compared with the HC group, the TRD group showed a wider range of altered striatal function than the nTRD group. In the TRD group, the HAMD-17 scores were positively correlated with the FC between the right VRP and the left caudate. This study provides new insights into understanding the specificity of TRD striatal circuits.

The influence of Sn doping on improvement of minority carrier lifetime (MCL) of Fe contaminated directionally solidified p-type multi-crystalline Si ingots is studied. The macrostructure and resistivity distribution of the Si ingots indicate that no significant difference exists with and without Sn doping. The average MCL increase by 26.2%, 31.8%, 8.1% with 20 ppmw, 40 ppmw, 60 ppmw Sn doping, respectively. The MCL was improved evidently due to the reduction of formation of interstitial Fe, FeB. The doping of Sn promotes formation of vacancies, which also contributes to passivation of interstitial Fe and FeB. A calculation of constitutional supercooling is carried out, which shows that Fe have great influence on the solidification interface stability, and Sn have little influence on the interface stability.

Silicon/carbon composite anodes with void space are widely touted as a promising candidate for lithium-ion batteries (LIBs), providing a good volume change tolerance to maintain the integrity of the electrodes. However, the void space is usually created by complicated and environmentally-unfriendly methods with corrosive HF. Herein, a 3D hierarchical porous carbon framework supported silicon-based composite with void space (Si@Voids@PC) is synthesized by diluted HCl-assisted etching a self-assembly CaCO3 template method coupled with pyrolysis of citric acid as the carbon source. The Si@Voids@PC electrode exhibits reversible capacity retention of 1527 mAhg−1 at 200 mAg−1 after 200 cycles with an initial discharge specific capacity of 3060.6 mAhg−1 and an initial Coulomb efficiency of 74.4%, which is superior to most of that in the reported literatures. This unique structure can not only provide more pathways for lithium ion diffusion and electron transfer but also maintain the integrity of the electrodes. Besides, the effect of lithiation behavior on the solid electrolyte interphase (SEI)-related problems is observed and discussed. This work might provide a facile and green method to synthesize silicon-based anodes with excellent electrochemical performance, and it also can be applied to the design of other materials with porous architecture.

With the rapid growth of the photovoltaic (PV) industry, the amount of the silicon waste has substantially increased, resulting in serious environmental problems. This waste mainly consists of the silicon waste powder from kerf loss slurry of wire saw wafer cutting process and the scrap pieces from silicon ingot casting process. To reduce the cost of crystalline Si production and relief the existing environmental pollutions, it is of significant interest to recover and recycle the silicon value from the Si waste. This paper presents a literature overview of the current technologies and research progress in the recovery and recycling of high purity silicon from the silicon wastes generated in the PV industry. First, the source and classification of Si wastes, including slicing silicon waste and scraps of Si ingots are summarized. Second, various techniques related to the separation and recovery of high purity Si from the waste are reviewed and compared based on the experimental results. The characteristics and advantages of different technologies are evaluated based on the current conditions. Third, the applications of silicon waste are explored in a detailed manner. Last, the assessment of different Si recovery technologies is elaborated. This review gives an outlook on the recycling and recovery of high purity silicon from the silicon waste, which shows great potential for further research in this field.

Many research works demonstrate that an appropriate size and porosity of Si can effectively alleviate the problem of large volume change. Although there are many methods to tune the size and porosity of Si, high cost and complicated processes hinder them from a large-scale application. Here a simple method is developed by ball milling and acid etching Al–Si alloy ingots with high Si contents. The porosity and size distribution of the obtained porous Si (P–Si) can be tuned effectively by adjusting the Si content in the Al–Si alloy. As a result, with Si content of 50 wt% in the Al–Si alloy ingot, P–Si50 presents relatively small and uniform particle size distribution, and the largest pore volume. After carbon coated, the obtained P–Si50/C maintains a reversible capacity of 1226 mAh g−1 after 200 cycles at a 0.2C current density. The method might provide a significant scientific contribution to further understanding of P–Si synthesized by the Al–Si alloy and guidelines for structure optimization of the P–Si for advanced lithium ion battery applications.

Although Al–Si alloy with low content of Si has often been used to synthesis anode materials mainly due to the high porosity of the obtained Si powders, it still suffers many problems, such as low Si powder yield and a large amount of acid consumption. In this research, the problem that the low porosity of Si powder synthesized by Al–Si alloy with a high content of Si (Al-70 wt% Si alloy ingot) is solved by simply changing the sequence of the acid etching and ball-milling of the Al–Si alloy. As a result, with the protection of the Al matrix during the ball-milling process, the obtained porous Si powder (Si70) has a high porosity. In addition, a low-priced but excellent cationic surfactant, Poly (propylene glycol) bis (2-aminopropyl ether) (PEA) is used to assist carbon coating, which leads to a uniform carbon coating on the Si surface and the formation of a cross-linked carbon structure. As a result, the obtained Si/C electrode (Si70 P/C) maintains a reversible capacity of 1110 mAh g−1 at the 200th cycle at a current rate of 0.2C. Moreover, based on SEM/TEM observation and electrochemical characterization, the hypothetical action mechanism of PEA is also discussed.