Alkali PolySulphide Flow Battery

A lithium ion flow battery comprising:

• a flow battery electrochemical cell comprising an anode half-cell and a cathode half-cell separated by an ion-selective separator, the electrochemical cell having at least one liquid electrode or electrolyte and which comprises a lithium polysulfide catholyte;
• at least one electrolyte reservoir and a flow circulation system for facilitating flow of electrolyte to and from the electrochemical cell and electrolyte reservoir;
• and
• a power convertor for two way conversion of current to and from the electrochemical cell and a load or supply,
• wherein the:
• ion-selective separator comprising a lithium ion conducting separator film for separating the anode half-cell and the cathode half-cell, a carbon layer disposed to a cathode side of the film and a lithium ion conductor layer disposed to an anode side of the carbon layer;
• the flow battery further comprising an electrolyte flushing system for flushing an electrolyte through the electrochemical cell in a short burst or pulse, which system is configured to cause electrolyte to be circulated at an increased flow rate for a pre-determined or determined duration in dependence of a pre-defined trigger so as to inhibit precipitation of highly lithiated lithium polysulfide species in the electrochemical cell during a discharge cycle.