However, nickel–cadmium batteries have low energy density compared to nickel–metal hydride and lithium–ion batteries. Another apparent disadvantage of nickel–cadmium battery is the so-called memory effect which makes periodical full discharge necessary.
Batteries using nickel negative electrodes are commonly called nickel-based batteries or simply nickel batteries. The first commercial battery system based on nickel electrode was nickel–cadmium, invented in 1899.
Nickel-cadmium batteries were later redesigned and improved by Neumann in 1947 where he succeeded in producing a sealed battery cell by re-combining gases from the reaction of battery components which is the current design of nickel cadmium batteries .
The nickel electrode, which has layered structure, can be paired with cadmium, iron, zinc, metal hydride, and even hydrogen negative electrodes. Nickel–cadmium battery was invented in 1899 by Waldemar Jungner from Sweden. The first sealed version was accomplished in 1947 by Neumann and this paved the way to modern nickel–cadmium batteries.
Despite the predominant role of lead–acid batteries in industrial standby and traction applications and the increasing importance of Lithium-ion batteries in both consumer and professional markets, nickel-based alkaline batteries have maintained over the past century a consistent market share of highly demanding industrial applications.
In Ni-Cd batteries, cadmium hydroxide is reduced to metallic cadmium at the negative electrode during charge, according to reaction (14.2): (14.2) Cd ( OH) 2 + 2 e − → Cd + 2 OH − E 0 − = − 0.81 V vs SHE