The device 9, wherein the medium is selected to facilitate {HEAD ~ diffusion} of intercalating ions between {TAIL ~ the first and second electrodes} 
The device 9 , wherein the medium is selected to facilitate { HEAD ~ diffusion } of intercalating ions between { TAIL ~ the first and second electrodes }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL