First you should select a knife that is durable. A fixed blade knife is best for using in most cases outdoors. You'll want a steel fabricated knife that is temper treated. When it comes to knives it really all comes down to comfort and use. In this case a fixed blade knife serves a better purpose and can take the abuse of being hammered on using the batoning method. You will also want a blade that is not serrated.
A knife is a great tool to use for splitting wood. It offers control for precision cutting while conserving energy. Some people use the batoning method and some do not. However the technique is good if you find that you need to rely on it. I use this method and stand by it's useful purpose.
The concern to others is that it dulls or potentially damages the blade. Really the only way to maintain a knife is to keep it sharp and know its limits. Yes there is a risk to damage, that's why I suggest having a sturdy, durable knife. If you practice this method you will become proficient with the technique and this will help to limit breaking or chipping the blade. First step is selecting the wood that you will use to club with on the back side of the blade. Ensure the surface is smooth and has the correct thickness and weight to hammer down with on the back edge.
When selecting the wood that you are about to baton, avoid knots and joints in the wood. Always remember safety first with proper eye protection. The last thing anyone needs is flying debris to get in your eyes.
You want to keep your knife perpendicular to your body and the ground. Also before you come down with full force ensure the blade of the knife is set in the wood first.
Batoning is a great way to make a fire board or hearth. Additionally kindling for fire for creating coals that will burn larger pieces of dry wood. This method is not to replace using an axe, however if you do not have an axe this is a good alternate.
Avoid splitting wood down the center and work on removing strips of wood. This will put less wear and tear on your knife.
Using a wooden wedge to split wood with is a good way to conserve your knife. All you need to do is carve a hard wood into the shape of a wedge. Then you baton the wedge down a log that has a natural split or crack. This method will not work on green wood or freshly cut wood from a living tree. You'll want to stick with dead, dry wood. Woods rich with resin will also be harder to split with a wooden wedge.