Three-parameter Weibull distribution is one of the preferable distribution models to describe product life. However, it is difficult to estimate its location parameter in the situation of a small size of sample. This ...Three-parameter Weibull distribution is one of the preferable distribution models to describe product life. However, it is difficult to estimate its location parameter in the situation of a small size of sample. This paper presents a stochastic simulation method to estimate the Weibull location parameters according to a small size of sample of product life observations and a large amount of statistically simulated life date. Big data technique is applied to find the relationship between the minimal observation in a product life sample of size <em>n</em> (<em>n</em> ≥ 3) and the Weibull location parameter. An example is presented to demonstrate the applicability and the value of the big data based stochastic simulation method. Comparing with other methods, the stochastic simulation method can be applied to very small size of sample such as the sample size of three, and it is easy to apply.展开更多
As an effective and competitive supplement to the commercialized lithium ion batteries(LIBs),sodium ion batteries(SIBs)have been receiving increasing attention in recent years due to lower cost,richer content,and broa...As an effective and competitive supplement to the commercialized lithium ion batteries(LIBs),sodium ion batteries(SIBs)have been receiving increasing attention in recent years due to lower cost,richer content,and broader distribution of sodium[1–7].Sodium has similar electrochemical properties to lithium,and thus the concepts for the preparation of electrode materials for SIBs can be borrowed from LIBs[8,9].展开更多
Compared with solid alkali metal anodes(Li, Na, K), liquid metal anodes(LMAs) could enable high-energy batteries due to their unique advantages, such as self-healing property and no dendrites. Among LMAs,liquid Na-K a...Compared with solid alkali metal anodes(Li, Na, K), liquid metal anodes(LMAs) could enable high-energy batteries due to their unique advantages, such as self-healing property and no dendrites. Among LMAs,liquid Na-K alloy anode has become a hotspot due to its high theoretical capacity, low redox potential and formation at room temperature(RT). However, it is challenging to utilize liquid Na-K alloy directly and independently as an electrode;and the high surface tension makes it more difficult to immerse into porous current collectors at RT. Herein, an amorphous hollow carbon film(AHCF) consisting of hollow spheres with significant surface defects has been designed to quickly infiltrate Na-K liquid alloy into the hollow carbon film at RT, forming a composite electrode(Na-K@AHCF). The symmetric cell with Na-K@AHCF could exhibit a cycle lifespan up to 400 h at 0.1 m A/cm^(2) and achieve stable stripping/deposition even at 5 mA/cm^(2). When matching with cathode material of sulfurized polyacrylonitrile(SPAN), the obtained K-S full cell exhibits good cycle stability and rate performance.展开更多
文摘Three-parameter Weibull distribution is one of the preferable distribution models to describe product life. However, it is difficult to estimate its location parameter in the situation of a small size of sample. This paper presents a stochastic simulation method to estimate the Weibull location parameters according to a small size of sample of product life observations and a large amount of statistically simulated life date. Big data technique is applied to find the relationship between the minimal observation in a product life sample of size <em>n</em> (<em>n</em> ≥ 3) and the Weibull location parameter. An example is presented to demonstrate the applicability and the value of the big data based stochastic simulation method. Comparing with other methods, the stochastic simulation method can be applied to very small size of sample such as the sample size of three, and it is easy to apply.
基金supported by the National Key R&D Program of China(Grant No.2017YFA0207202)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX20_1058)。
文摘As an effective and competitive supplement to the commercialized lithium ion batteries(LIBs),sodium ion batteries(SIBs)have been receiving increasing attention in recent years due to lower cost,richer content,and broader distribution of sodium[1–7].Sodium has similar electrochemical properties to lithium,and thus the concepts for the preparation of electrode materials for SIBs can be borrowed from LIBs[8,9].
基金financially supported by the National Natural Science Foundation of China (No. 51702155)。
文摘Compared with solid alkali metal anodes(Li, Na, K), liquid metal anodes(LMAs) could enable high-energy batteries due to their unique advantages, such as self-healing property and no dendrites. Among LMAs,liquid Na-K alloy anode has become a hotspot due to its high theoretical capacity, low redox potential and formation at room temperature(RT). However, it is challenging to utilize liquid Na-K alloy directly and independently as an electrode;and the high surface tension makes it more difficult to immerse into porous current collectors at RT. Herein, an amorphous hollow carbon film(AHCF) consisting of hollow spheres with significant surface defects has been designed to quickly infiltrate Na-K liquid alloy into the hollow carbon film at RT, forming a composite electrode(Na-K@AHCF). The symmetric cell with Na-K@AHCF could exhibit a cycle lifespan up to 400 h at 0.1 m A/cm^(2) and achieve stable stripping/deposition even at 5 mA/cm^(2). When matching with cathode material of sulfurized polyacrylonitrile(SPAN), the obtained K-S full cell exhibits good cycle stability and rate performance.
