The Static Barrier was a weapon that used the residual static electricity in the air to create a physical force field that could protect the user from enemy fire. Once the static barrier took a certain amount of damage, it failed, and had to be energized again. At V4 it upgrades to the Repulsor Field.
When the barrier is taken down Ratchet will be invincible for a few seconds. 
- Ratchet & Clank: Size Matters (first appearance)