What is the difference in performance between li-ion rechargeable battery and ni-mh rechargeable battery?

Li-ion rechargeable battery and ni-mh rechargeable battery are two common rechargeable battery technologies that have some significant differences in performance:

Energy density
Lithium-ion batteries: have higher energy density, which means that they can provide more power for the same volume or weight. This makes them ideal for portable electronic devices such as smartphones, laptops, and tablets.
NiMH batteries: have lower energy density, so they provide less power for the same volume.
Cycle life
Lithium-ion batteries: generally have longer cycle life, and can withstand hundreds to thousands of charge and discharge cycles, depending on the manufacturing quality of the battery and the conditions of use.
NiMH batteries: generally have shorter cycle life, but can still provide hundreds of charge and discharge cycles.
Charging speed
Lithium-ion batteries: support fast charging technology, which can charge more power in a shorter time, which is very useful for applications that require fast charging.
NiMH batteries: have relatively slow charging speeds and are not suitable for applications that require fast charging.
Memory effect
Lithium-ion batteries: have almost no memory effect, which means that they can be charged at any charge level without significantly affecting the battery's life.
NiMH: There is a certain degree of memory effect. If the battery is frequently charged without being fully discharged, it may cause the battery capacity to decrease.
Self-discharge rate
Lithium-ion battery: The self-discharge rate is low, and the battery power loss is relatively small even if it is not used for a long time.
NiMH: The self-discharge rate is high, and the battery power will decrease faster when it is not used for a long time.
Operating temperature range
Lithium-ion battery: Generally able to operate in a wide temperature range, with good performance from low temperature to high temperature.
NiMH: The performance at high temperature may not be as good as lithium-ion battery, but the performance at low temperature may be better.
Safety
Lithium-ion battery: Thermal runaway may occur under conditions (such as overcharge, overdischarge, high temperature or physical damage), causing the battery to overheat or even catch fire.
NiMH: Relatively safer, although it may also fail, it usually does not react violently like lithium-ion batteries.
Cost
Lithium-ion battery: Due to its high energy density and long life, although the initial cost may be higher, the long-term cost of use may be lower.
NiMH batteries: Low initial cost, but may cost more in the long term due to lower energy density and shorter lifespan.
Environmental impact
Lithium-ion batteries: Contain some heavy metals that are harmful to the environment, such as cobalt and lithium, and require proper recycling and disposal.
NiMH batteries: Although they also contain some heavy metals that need to be recycled, they are generally considered to have a lower environmental impact.
Application areas
Lithium-ion batteries: Widely used in portable electronic devices, electric vehicles, and energy storage systems.
NiMH batteries: Commonly used in low-power devices, some power tools, and hybrid vehicles.
In summary, lithium-ion batteries and NiMH rechargeable batteries each have advantages and disadvantages, and the choice of which battery depends on the specific application requirements, cost considerations, and environmental impacts.