However, {TAIL ~ conventional polymer electrolytes} have had {HEAD ~ the problem} that it is difficult to simultaneously satisfy ion conductivity and reliability 
However , { TAIL ~ conventional polymer electrolytes } have had { HEAD ~ the problem } that it is difficult to simultaneously satisfy ion conductivity and reliability
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH