Research played a key role by bringing together the evolving technical needs and opportunities with experimental science and applications. Electrochemical processes were widely used in the manufacture of much of the equipment used in the Bell System. Batteries were used in every Bell System central office to provide load leveling and backup power. Research on batteries began in Bell Laboratories in 1930. The main focus of the early battery work involved lead-acid batteries, rechargeable batteries that offered low cost, together with high power density. Research at Bell Laboratories in the late 1970s focused on cathode materials for high energy density lithium rechargeable batteries. The search was for an electronically conducting material that could be reversibly oxidized and reduced with little change to its shape and structure. Other research taking place at Bell Laboratories focused on different aspects of a possible lithium battery, especially conductive organic-based electrolytes and a commercially viable anode material. Starting in the late 1970s, Samar Basu and coworkers worked on these problems aiming to create a viable commercial lithium battery. Ultimately Sony Engineers combined the Bell Labs patents with a cobalt oxide cathode material pioneered by John Goodenough and his colleagues then at Oxford University to produce the first commercial lithium-ion battery, the basis for the batteries which power most modern rechargeable portable electronic devices.