Comparing the two, NiCD two way radio batteries has an advantage of a high number of charge/discharge cycles, if properly maintained, nickel-cadmium provides over 1000 charge/discharge cycles. A nickel-metal-hydride two way radio battery, on the other hand, starts with good capacity, but the performance starts to deteriorate after 200-300 cycles if repeatedly deeply cycled.

NiMH two-way radio batteries are less prone to memory effect than NiCD, requiring fewer exercise cycles. Nickel based batteries require regular full discharge to prevent crystalline formation. NiCD should be exercised once a month, NiMH once in every 3 months. NiMH batteries are environmentally friendly, contains only mild toxins; profitable for recycling.

Can I Substitute Li-Ion for NiCD/NiMH Two Way Radio Batteries?
If you are thinking of substituting your NiCD or NiMH batteries with a Li-Ion battery you would need to refer to your Icom two-way radio manual or manufacturer. Since li-ion batteries have a higher energy density usually two-way models are specifically designed to be used with li-ion batteries. However, more often than not, manufacturers are sticking to NiCD or NiMH batteries since they are less expensive to manufacture.