In 1836,John F. Daniell,an English chemist,developed an improved battery that produced a steadier current than earlier devices.Until this time,all batteries were primary,meaning they could not be recharged.In 1859,the French physicist Gaston Plante invented the first rechargeable battery.It was based on lead acid,a system that is still used today.
In 1899,Waldmar Jungner from Sweden invented the nickel-cadmium battery (NiCd),which used nickel for the positive electrode (cathode) and cadmium for the negative (anode).High material costs compared to lead acid limited its use and two years later,Thomas Edison produced an alternative design by replacing cadmium with iron.Low specific energy,poor performance at low temperature and high self-discharge limited the success of the nickel-iron battery.It was not until 1932 that Shlecht and Ackermann achieved higher load currents and improved the longevity of NiCd by inventing the sintered pole plate.In 1947,Georg Neumann succeeded in sealing the cell.
For many years,NiCd was the only rechargeable batteries for portable applications.In the 1990s,environmentalists in Europe became concerned about environmental contamination if NiCd were carelessly disposed;they began to restrict this chemistry and asked the consumer industry to switch to Nickel-metal-hydride (NiMH),an environmentally friendlier battery.NiMH is similar to NiCd,and many predict that NiMH or ni-mh battery will be the stepping-stone to the more enduring lithium-ion (Li-ion).
Most research activities today revolve around improving lithium-based systems.Besides powering cellular phones,laptops,digital cameras,power tools and medical devices,Li-ion or lithium battery is also used for electric vehicles.The battery has a number of benefits,most notably its high specific energy,simple charging,low maintenance and being environmentally benign.
Inventions in the 1700s and 1800s are well documented and credit goes to the dignified inventors.Benjamin Franklin invented the Franklin stove,bifocal eyeglasses and the lightning rod.He was unequaled in American history as an inventor until Thomas Edison emerged.Edison was a good businessman who may have taken credit for inventions others had made.Contrary to popular belief,Edison did not invent the light bulb; he improved upon a 50-year-old idea by using a small,carbonized filament lit up in a better vacuum.Although a number of people had worked on this idea before,Edison gained the financial reward by making the concept commercially viable to the public.The phonograph is another success story for which Edison received due credit.
Countries often credit their own citizens for having made important inventions,whether or not they deserve it.When visiting museums in Europe,the USA and Japan one sees such bestowment.The work to develop the car,x-ray machines,telephones,broadcast radio,televisions and computers might have been done in parallel,not knowing of others’ advancements at that time,and the rightful inventor is often not clearly identified.Similar uncertainties exist with the invention of new battery systems,and we give respect to research teams and organizations rather than individuals.