I DID say "excuse the sarcasm"!, I know diodes get hot, YOU know diodes get hot, but it must be common knowledge amongst manufacturers that they don,t, else why do we find the pcb charred black under so many of them? Check it out, you will find many bits of kit that still work, but with diodes that are about to unsolder themselves.
Coming back to the battery, it could well be failing to charge, through no fault of the battery. Please check that the charger circuitry works before throwing the battery away.