Ultracapacitors: Do your power supply design need sudden and short high power of energy which your batteries or other power source not capable of taking the load. Just have a look at using ultracapacitors. Ultracapacitors are suitable for many such power supply applications.
Ultracapacitor are new generation storage capacitors where the distance between electrodes is at nano meter level. They can store and release the electrical energy just like batteries but offers some specific advantage over batteries, i.e. exactly the solutions for the battery related problems you are facing.
Have a look at this comparison table of ultracaps v/s various batteries






