Hydrogen fuel cells are more expensive than batteries, because they either work at room-temperature and they need expensive catalysts using platinum-group metals, or they work at high temperatures and then they have a short lifetime, requiring frequent replacements of most components.
Also the efficiency of a cycle of storing energy into gaseous hydrogen and then recovering it is limited by fundamental reasons to low values.
For cars, it is likely that batteries will remain the best solution, due to the high efficiency of a charge-discharge cycle.
For long term storage of energy, further improvements of fuel cells might make them the best solution for recovering energy stored in chemical form, but not using gaseous hydrogen for storage, but other more appropriate substances, e.g. hydrocarbons, alcohols, ammonia or solid carbon.
There are fuel cells for the other fuels mentioned above and the only advantage of the hydrogen fuel cells is that they currently have the greatest power density, i.e. the speed of reaction of the hydrogen per area of electrode is for now the greatest (leading to the greatest electrical current density), but only either at high temperatures or when using expensive catalysts.
The mitochondria from all the cells of our body are a demonstration that it is possible to make a very high efficiency fuel cell using hydrocarbons as fuel and without using any rare or expensive materials for catalysts.
While the solar cells already exceed the efficiency of plants at capturing solar energy, the artificial fuel cells have a long way until becoming competitive with those used by the living beings.
Also the efficiency of a cycle of storing energy into gaseous hydrogen and then recovering it is limited by fundamental reasons to low values.
For cars, it is likely that batteries will remain the best solution, due to the high efficiency of a charge-discharge cycle.
For long term storage of energy, further improvements of fuel cells might make them the best solution for recovering energy stored in chemical form, but not using gaseous hydrogen for storage, but other more appropriate substances, e.g. hydrocarbons, alcohols, ammonia or solid carbon.
There are fuel cells for the other fuels mentioned above and the only advantage of the hydrogen fuel cells is that they currently have the greatest power density, i.e. the speed of reaction of the hydrogen per area of electrode is for now the greatest (leading to the greatest electrical current density), but only either at high temperatures or when using expensive catalysts.
The mitochondria from all the cells of our body are a demonstration that it is possible to make a very high efficiency fuel cell using hydrocarbons as fuel and without using any rare or expensive materials for catalysts.
While the solar cells already exceed the efficiency of plants at capturing solar energy, the artificial fuel cells have a long way until becoming competitive with those used by the living beings.