Abstract The operation of underwater vehicles in deep-sea depends on onboard battery completely, while the development of deep-sea battery is seriously hindered by extreme environment of deep-sea, mainly including hydraulic pressure, low temperature and seawater conductivity. Therefore, it derives specialized design of deep-sea battery, involving power generation, protection, distribution and management. The development of deep-sea battery has experienced several generations, and it turns to Li battery in recent decades by the exclusive virtues exampled as larger energy density as well as less operational risk. The rapidly growing deep-sea Li battery has boosted underwater vehicles development successfully, while there are still many issues unresolved for improving deep-sea Li battery. This review firstly presents the whole picture of deep-sea battery manufacturing systematically, especially about deep-sea Li battery as current mainstream of underwater power. Then it expands the discussion on developing deep-sea Li battery, including materials selection based on electro-chemo-mechanics model, modification and test on components, battery management system specialized on software and hardware. Finally, it discusses the crucial issues for increasing the utilization of deep-sea battery, and proposes promising development directions. Based on systematic reflection on deep-sea battery and discussion on deep-sea Li battery, this review is expected to provide research fundamental of developing underwater power for extreme environmental exploration.
The solid diffusion coefficient of Li-ion in C/LiNiMnCoO2 battery was measured by capacity intermittent titration technique (CITT) under different voltages and different charge/discharge cycles. The results show that the diffusion coefficient appears a minimum peak at 3.7 V which is flatted gradually with increasing charge/discharge cycles. The values of solid diffusion coefficient tend to increase from 2×10-11 cm2/s to 4×10-11 cm2/s at 3.5 V and decrease from 2×10-11 cm2/s to 5×10-12 cm2/s at 3.8-4.2 V.
The electrochemical insertion of Li into graphite initiates a series of thermodynamic and kinetic processes. An in-depth understanding of this phenomenon will deepen the knowledge of electrode material design and optimize rechargeable Li batteries. In this context, the phase transition from dense stage II (LiC12) to stage I (LiC6) was comprehensively elucidated in a graphite anode via both experimental characterizations and first-principles calculations. The results indicate that, although the transition from stage II to stage I is thermodynamically allowed, the process is kinetically prohibited because Li ions tend to cluster into stage compounds rather than form a solid solution. Additionally, the phase transitions involve at least three intermediate structures (1T, 2H, and 3R) before reaching the LiC6 (stage I) phase. These findings provide new insights into the electrochemical behavior of graphite and the electrode process kinetics for rechargeable Li batteries.
Geologic condition and features of Qinshui basin were introduced.Then taking the Hudi area as an example,the design research on bottom hole assembly for coal bed gas directional well was carried out,and the bottom hole assembly of coal bed gas directional well was also given and was applied in site construction,good result was gained,which can provide some experiences for development of coal bed gas by using the directional well technology.
The corrosion texture of polycrystalline silicon was one of the methods to improve the efficiency of polycrystalline silicon solar cells.Besides HF-HNO3 method.Some new corrosion texture technologies of polycrystalline silicon were researched.In this paper,technology of improved acidic corrosion texture and alkaline corrosion texture for multicrystalline silicon were introduced,and these new technologies were evaluated.
LiNi1/3Co1/3Mn1/3O2 is a widely used commercial cathode material in the fields of consumer electronics and electric vehicles. However, its energy density still falls short of the standard and needs to be improved. The most effective method is to increase the cut-off voltage, but this will result in a drop in capacity. In this study, a LiF layer is coated on the surface of LiNi1/3Co1/3Mn1/3O2 via an in situ method. It is found that the LiF layer may protect materials from side reactions with electrolytes, improve the interfacial stability, and enhance the cyclic performance. The bare sample shows relatively poor cycling stability, with capacity retention rates of 65.9% (0.2 C) and 12.8% (5 C) after 100 cycles, while 1% LiF-coated NCM has higher cycling stability with capacity retention rates of 83.4% (0.2 C) and 73.3% (5 C) after 100 cycles, respectively. Our findings suggest that a LiF surface layer could be a useful means of boosting the electrochemical performance of NCM cathode materials.
Abstract : This report is a translation of a book received by USACRREL as part of its cooperative program with the Institute of Glaciology and Cryopedology, Academica Sinica, People's Republic of China. The bibliography covers the following topics: glaciers by geographic regions, applied glaciology including snow, avalanches, and river ice, permafrost (cryopedology), mud flows, and survey techniques including mapping, remote sensing, and isotope analyses. A list of Chinese journals is included. (Author)
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