The NiMh battery similar to the Li-Ion battery is a rechargeable source of energy. This battery largely differs in the constituents of the cathode, anode and the electrode. Speaking about the constituents let’s just jolt down the details about the electrode and the electrolyte. On the positive electrode it consists of Nickel Hydroxide while on the negative electrode we have a hydrogen alloy which constitutes of hydrogen. The electrolyte is an alkaline solution of potassium hydroxide. The process of the generation of electricity is similar to that in any cell with a cathode, anode and electrode.
The NiMh batteries are really cost effective but due to its heavy weight it has not been able to create its own space in the market of gadgets. The power retaining capacity of this battery is very similar to the other batteries like Li-Ion ones .But the set back here is that the NiMh battery take a very long time to charge! This is definitely a problem for the electronic gadget users. Reason being that they are also looking for such power backups which can give them infinite time access to the phone without charging.
Apart from the fact of it being rechargeable and cost effective the opposite aspect of this battery is that they are not capable of delivering full power at a low battery state of say 40%. Whereas, talking about the batteries like Li-Ion for instance gives full power at any battery state be it 100% or 20%. These small differences between the Li-Ion batteries and the NiMh batteries have created a long distance for NiMh batteries to travel!
The NiMh has a very small market under its control and gradually Li-ion batteries are taking over it as well. The few of the places where NiMh batteries has its marks are UPS, electronic gadgets like cameras, small voltage appliances like trimmers. These batteries also prone to memory effect which hampers the charge retaining capacity of the battery to a very great extent. Each time you charge the phone would then be considered as a cycle irrespective of the fact weather the phone was then fully charged or just left on there for a few minutes.
These batteries could have given the Li-Ion batteries a very good competition only if the discharging rate was not so high. The other known fact is that these batteries have low internal impedance which again causes a problem in the flow of electron. This has given the NiMh batteries a very huge set back in the market of batteries. Although, NiMh batteries have still been able to find space in the high voltage sectors like auto mobiles since NiMh batteries can stand high temperature which unfortunately Li-Ion batteries cant. Also the pricing of the NiMh batteries is almost half as that of the Li-Ion batteries but yet it has a far way to come in the other sectors as well.