异步电动机倍极比变极绕组新探

提出倍极比变极新方法,以扩大变极绕组的选择范围,从中选出较佳的变极方案,并能针对不同情况消除某次谐波,改善电机性能。

Porous honeycomb-like C3N4/rGO composite as host for high performance Li-S batteries

Lithium-sulfur (Li-S) batteries have attracted extensive attention along with the urgent increasing demand for energy storage owing to the high theoretical specific capacity and energy density, abundant reserves and low cost of sulfur. However, the practical application of Li-S batteries is still impeded due to the low utilization of sulfur and serious shuttle-effect of lithium polysulfides (LiPSs). Here, we fabricated the porous honeycomb-like C3N4 (PHCN) through a hard template method. As a polar material, graphitic C3N4 has abundant nitrogen content (-58%), which can provide enough active sites to mitigate shuttle-effect, and then conductive reduced graphene oxide (rGO) was introduced to combine with PHCN to form PHCN/rGO composite in order to improve the utilization efficiency of sulfur. After sulfur loading, the PHCN/rGO/S cathode exhibited an initial discharge capacity of 1,061.1 mA h g^-1 at 0.2 C and outstanding rate performance at high current density of 5 C (495.1 mA h g^-1), and also retained 519 mA h g^-1, after 400 cycles at 1 C. Even at high sulfur loading (4.3 mg cm^-2), the capacity fade rate was only 0.16% per cycle at 0.5 C for 200 cycles. The above results demonstrate that the special design of PHCN/rGO composite as sulfur host has high potential application for Li-S rechargeable batteries.

In-situ electropolymerized bipolar organic cathode for stable and high-rate lithium-ion batteries

To address the dissolution issue and enhance the electrochemical performance of organic electrode materials,herein, a bipolar organic cathode was prepared by in-situ electropolymerization of amino-phenyl carbazole naphthalene diimide(APCNDI). APCNDI is composed of n-type 1,4,5,8-naphthalene tetracarboxylic diimide that stores Li cations and p-type carbazole groups which react with anions and serve as polymerization sites. Electropolymerization completely eliminated the dissolution problem of APCNDI, and the electropolymerized cathode demonstrated a bipolar reaction with excellent electrochemical performance, stable cycling performance with a capacity retention of 92 mA h g;after1000 cycles, and a superior rate performance of 72 mA h g;at 10 A g;. The bipolar feature and reactions of APCNDI were systematically investigated and verified by multiple characterization techniques. Our findings provide a novel strategy for the design and fabrication of electrodes for high-performance organic batteries.

A unique co-recovery strategy of cathode and anode from spent LiFePO_(4) battery

Along with the explosive growth in the market of new energy electric vehicles,the demand for Li-ion batteries(LIBs)has correspondingly expanded.Given the limited life of LIBs,numbers of spent LIBs are bound to be produced.Because of the severe threats and challenges of spent LIBs to the environment,resources,and global sustainable development,the recycling and reuse of spent LIBs have become urgent.Herein,we propose a novel green and efficient direct recycling method,which realizes the concurrent reuse of LiFePO_(4)(LFP)cathode and graphite anode from spent LFP batteries.By optimizing the proportion of LFP and graphite,a hybrid LFP/graphite(LFPG)cathode was designed for a new type of dualion battery(DIB)that can achieve co-participation in the storage of both anions and cations.The hybrid LFPG cathode combines the excellent stability of LFP and the high conductivity of graphite to exhibit an extraordinary electrochemical performance.The best compound,i.e.,LFP:graphite=3:1,with the highest reversible capacity(~130 mAhg^(-1) at 25 mAg^(-1)),high voltage platform of 4.95 V,and outstanding cycle performance,was achieved.The specific diffusion behavior of Li^(+) and PF_(6)^(-) in the hybrid cathode was studied using electrode kinetic tests,further clarifying the working mechanism of DIBs.This study provides a new strategy toward the large-scale recycling of positive and negative electrodes of spent LIBs and establishes a precedent for designing new hybrid cathode materials for DIBs with superior performance using spent LIBs.