Low-cost all-iron flow battery with high performance towards long-duration energy storage

Long duration energy storage(LDES)technologies are vital for wide utilization of renewable energy sources and increasing the penetration of these technologies within energy infrastructures.Herein,we propose a low-cost alkaline all-iron flow battery by coupling ferri/ferro-cyanide redox couple with ferric/ferrous-gluconate complexes redox couple.The designed all-iron flow battery demonstrates a coulombic efficiency of above 99%and an energy efficiency of~83%at a current density of80 m A cm^(-2),which can continuously run for more than 950 cycles.Most importantly,the battery demonstrates a coulombic efficiency of more than 99.0%and an energy efficiency of~83%for a long duration(~12,16 and 20 h per cycle)charge/discharge process.Benefiting from the low cost of iron electrolytes,the overall cost of the all-iron flow battery system can be reached as low as$76.11 per k Wh based on a10 h system with a power of 9.9 k W.This work provides a new option for next-generation cost-effective flow batteries for long duration large scale energy storage.

Effect of high-pressure detonation products on fuel injection and propagation characteristics of detonation wave

The effect of high-pressure detonation products on fuel injection and propagation characteristics of detonation wave has been investigated in the form of ion voltage by varying the equivalence ratio(ER),air mass flux,and operation duration with hydrogen-air mixtures.It has been shown experimentally that the ion voltage decays gradually during the initial stage of rotating detonation wave(RDW).The attenuation of ion voltage is a general phenomenon,and the decay rate of ion voltage and its peak value of the trough state are related to the equivalence ratio and air mass flux.The analysis of interaction between the combustor and hydrogen plenum indicates that the feedback of high-pressure detonation products leads to the attenuation of ion voltage.In addition,the long-duration tests show that the ion voltage will recover to a steady state with the extension of reaction time,when the purgation(products leaving plenums)of detonation products is greater than feedback(products entering plenums)of detonation products in the hydrogen plenum.The recovery of ion voltage starts earlier at the higher equivalence ratio and air mass flux,and the peak value of ion voltage in the steady state also increases with the increase of equivalence ratio and air mass flux.A low frequency oscillation about 10 e12 Hz occurs in the RDW at some operation conditions.This low frequency oscillation is related to the interaction between the combustor and hydrogen plenum,and can be eliminated by either increasing the equivalence ratio or decreasing the air mass flux.

Fast optimization of impulsive perturbed orbit rendezvous using simplified parametric model

A novel simplified parametric model for long-duration impulsive orbit rendezvous is proposed.Based on an existing fast estimation method,the optimal impulses and trajectory can be expressed by only ten parameters whose initial values can be easily determined.Then,these parameters are used to predict orbital deviations with a target orbit.A simple correction process is designed to sequentially update the parameters based on the J_(2) perturbed analytical dynamic equations of circular orbits.Finally,an iteration loop is formed to obtain the precise parameters and optimal trajectory.The simulation results confirm that the simplified parametric optimization method can be applied to elliptical orbits of small eccentricity and adapts well to both analytical and high-precision dynamics.The deviations could always converge within five iterations and the calculation was more efficient than the existing methods.