This layer is formed on the particles of positive electrode material by precipitation from {HEAD ~ a cobalt salt solution}, which can be {TAIL ~ a cobalt sulfate solution} 
be
This layer is formed on the particles of positive electrode material by precipitation from { HEAD ~ a cobalt salt solution } , which can be { TAIL ~ a cobalt sulfate solution }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL