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Synthesis and control strategy of colloidal nanocrystals are mainly concerned with dynamic factors. Generally, theory of nucleation of liquid phase colloids and crystal growth are considered. Firstly, the strategies on colloidal nanocrystalline synthesis and morphology control at the stage of nucleation, growth and ripening were reviewed in this paper. Secondly, selective-adsorption mechanism, effective-monomer mechanism and oriented-attachment mechanisms were briefly introduced for the phenomena that can not be explained by classical crystal growth theory. It was also introduced briefly the joint action of some new mechanisms or multiple mechanisms on synthesis of nano-materials in recent years. Finally, perspectives on future development of nanocrystalline synthesis and morphology control were presented. It is believed that quantitative and precise structural control is of great importance and will be a huge challenge and development trend in nanocrystalline synthesis and morphology control.

Carbon solely can form a lot of nanostructures, such as zero-dimensional nanosphere, one-dimensional nanotube and two-dimensional graphene. They perform differently in Li-ion and Li-S batteries. It is worth noting that CNTs and graphene are not appropriate to be used as electroactive materials for Li-ion or Li-S batteries for four reasons. First, when CNTs and graphene are used as an anode, they often exhibit high specific capacities during the first lithiation step, but a large fraction of lithium ions is irreversibly consumed instead of reversibly stored, leading to a low Coulombic efficiency of the cell. Second, a graphene-based anode has a large voltage hysteresis in the charge/discharge curves. Third, it has been reported a CNT-based anode lacks a steady voltage plateau with large change in voltage during discharge. Fourth, despite their high initial capacities, graphene and CNT-based anodes often suffer from fast capacity decay after a few tens of cycles. Continuous efforts have been made to build better lithium batteries with a higher energy density and wider applicability, including both current state-of-the-art Li-ion batteries and near-term Li-S batteries. Because the behavior of a rechargeable battery is mainly based on the performance of its anode and cathode, designing advanced electrode materials as well as electrode with tailored compositions and structures has been the hot topic in recent years. The role of carbon nano-materials to construct electrode materials and tailored electrodes in Li-ion and Li-S batteries in high performance was reviewed in the paper from three aspects. Firstly, the role of carbon nano-materials in modifying the electroactive materials was discussed from three aspects:electron- and ion-transport facilitators, immobilization sites and volume expansion buffering. Secondly, the role of carbon nano-materials in optimizing the inactive components was considered as follows:conducting additives, current collectors and conductive interlayers. Thirdly, the role of carbon nano-materials in designing the bendable and stretchable devices are discussed from three aspects:conductive phases in nonconductive substrates, flexible current collectors and freestanding composite electrode. Finally, perspectives on future development of Li-ion and Li-S batteries were presented. It is considered that multi-functional carbon nano-materials will be main research focus in the future.

Abstract: The hierarchical carbon-coated LiFePO4 nano-grain microspheres are prepared by a chemical co-precipitation method. The microstructure and electrochemical properties of LiFePO4/C composites treated at 950–1025 K are intensively investigated. The rate discharge capability has been obviously enhanced when sample is treated at 1025 K. This attributes to its improved electric conductivity of 0.09 S cm−1 due to the in-situ formation of Fe2P phase. The cycling stabilities are excellent until 300 cycles for all the samples at the rate 1C in discharge, which is very difficult to reach for nano-grains with large specific surface area and high reaction activity. Our samples with hierarchical microstructures exhibit high Li-ion diffusion rate (10−9–10−13 cm2 S−1) with enhanced tap density (1.30 g cm−3). It is considered in our paper that the rate capacities increased by Li-ion diffusion rate are not as obvious as electric conductivity. Therefore, the LiFePO4/FePO4 reaction is a non-diffusional controlled process. [Copyright &y& Elsevier]

Challenges remain to show good capacitive performance while achieving high loadings of active materials for supercapacitors. Trying to realize this version, a nickel-protecting carbon fiber paper@Co-doped NiS x (Ni-CP@Co-NiS x ) electrode with high specific gravimetric, areal, and volumetric capacitance is reported in this work. This free-standing electrode is prepared by an electroplating-hydrothermal-electroplating (EHE) three-step method to achieve a high loading of almost 26.7 mg cm -2 . The cobalt-doping and nickel-protection strategies effectively decrease the impedance and inhibit the active material dropping from the electrode resulting from the expansion stress, which endows the Ni-CP@Co-NiS x electrode with a high rate and good cycling performance, especially with an ultrahigh specific areal/volumetric/gravimetric capacitance of 53.3 F cm -2 /2807 F cm -3 /1997 F g -1 at 5 mA cm -2 , respectively. Employing activated carbon functionalized with riboflavin (AC/VB2) as a negative electrode, the asymmetric supercapacitor device delivers a very high energy density of up to 60.4 W h kg -1 . This work demonstrates that electrodes with a high loading density and excellent performance can be obtained by the combination of the EHE method to adjust the internal conductivity and external structural stability.

Background: Whether right ventricular outfow tract septum (RVOTS) pacing is superior to right ventricular apex (RVA) pacing with respect to left ventricular synchrony, cardiac function, and remodelling in the elderly with normal left ventricular ejection fraction (LVEF), is still unknown., Aim: To assess the impact of RVOTS vs. RVA pacing on the cardiac performance of the elderly with normal LVEF during a long-term observation., Methods: From 2007 to 2010, 65 patients with standard pacing indications for permanent pacing were recruited and randomised to receive RVA (32 patients) or RVOTS pacing (33 patients). Over a median 28 months' follow-up, available data was summarised, including New York Heart Association (NYHA) functional class, echocardiographic and pacing parameters, axis, QRS duration and plasma B-type natriuretic peptide (BNP) level. Then these values were compared between the RVA group and the RVOTS group, as well as between pacemaker pre- and post-implantation in the RVA group and in the RVOTS group, respectively., Results: There were no significant differences in baseline characteristics between the RVA group and the RVOTS group. The median pacing durations did not differ significantly between the groups (31.5 months in the RVA group vs. 28 months in the RVOTS group, p = 0.728). Compared to the baseline values, LVEF decreased with RVA pacing (from 59.5 ± 6.21 to 54.22 ± 8.73, p = 0.001), but LVEF did not markedly vary in the RVOTS group (57.82 ± 6.06 and 56.94 ± 5.54, p = 0.152). The number of patients with moderate tricuspid valve regurgitation remarkably increased in the RVA group, from six (18.75%) patients to 10 (31.3%) patients, preoperatively to postoperatively (p = 0.046), but this change was not statistically significant in the RVOTS group. Compared to the RVOTS group, NYHA functional class had a deteriorated tendency in the RVA group (p = 0.071). After the implantation, the increase of median BNP level was observed in the RVA group (35 pg/mL at preimplantation and 50 pg/mL at the end of follow-up, p = 0.007); No significant change was obtained in the RVOTS group (36.4 pg/mL at pre-implantation vs. 38 pg/ml at the end of follow-up, p = 0.102). Compared to the RVA pacing group, the mean QRS width narrowed substantially in the RVOTS pacing group (from 143.56 ± 12.90 to 105.52 ± 15.21, p = 0.000). In terms of the end diastolic and systolic diameters of the left ventricular, there were no statistical variations observed during the follow-up., Conclusions: Permanent RVA pacing in elderly patients with normal LVEF led to left ventricular systolic function deterioration denoted by lower LVEF and higher BNP level. When compared to RVA pacing, RVOTS pacing had no remarkable benefit in terms of preventing cardiac remodelling.