If you have an ebike, the quick answer is no - using a higher voltage battery will not improve performance and could potentially damage your bike.
To understand why, it's important to know how ebikes work. Most ebikes on the market today use brushless DC motors. These types of motors are designed to run on specific voltages - usually between 24 and 48 volts. The motor controllers that regulate the power going to the motor are also tuned to a specific voltage range.
Using a higher voltage battery than what your bike is designed for can throw off the delicate balance between the motor and controller, leading to reduced performance or even damaging your bike. In some cases, it may be possible to re-tune the controller to work with a higher voltage battery - but this is definitely not something that should be attempted by someone who isn't experienced in working with electrical systems.
If you're looking to get more power out of your ebike, there are other ways to do it without resorting to using a higher voltage battery. One option is to install a larger motor - this will give you more torque, making it easier to pedal up hills or accelerate from a stop. You can also upgrade your existing motor controller to one that can handle more power, giving you more control over how much juice goes to your motor.
Of course, if you're really looking for a challenge, you could always try building your own ebike from scratch! This way you can design everything exactly how you want it, including choosing which batteries and components will work best together. But if you're not an experienced mechanic or electrician, we wouldn't recommend taking this route unless you're prepared for some serious trial and error (not to mention spending some time reading up on electrical theory!).