Honda said Wednesday it will start recycling rare earth metals and other key materials in hybrid auto batteries this year — a key innovation in the Japanese carmaker's effort to be green.

Japan depends on imports, mostly from China, for rare earth elements, which are essential for making high-tech products. But a steady supply has been periodically threatened over political disputes with China.

What are rare earth elements?

Rare earth elements, also known as rare earth metals, are a group of heavy metals that retain their physical properties at high temperatures. The body responsible for chemical nomenclature, the International Union of Pure and Applied Chemistry, considers 17 elements to be part of the group, though other groups use a slightly different definition.

Rare earth elements are used for everything from nickel metal hydride batteries in hybrid cars to fibre-optic telecom cables, military hardware, solar panels, wind turbines, compact fluorescent lighting, mobile phones, computers, the manufacturing of super conductors and high-energy magnets and petroleum refining.

Beijing, meanwhile, has defended its export limits on its rare earths as an environmental measure and rejected a World Trade Organization challenge by the United States, Europe and Japan. China has about 30 per cent of global deposits of rare earths, but accounts for more than 90 per cent of production.

Honda officials said the company was targeting September or October to begin recycling of rare earths. They said it would be a first for the auto industry.

Honda Motor Co. president Takanobu Ito said the move to recycle the metals is part of a broader push by the company to try to reduce pollution and global warming. The effort includes experimental projects to combine solar power with fuel-cell cars — what Ito called the Honda "dream" to derive energy solely from nature and emit just water.

"In the long term, we hope to move to renewable energy sources that won't harm the environment," he said at headquarters in Tokyo.

Fuel cells are powered by the energy created when hydrogen combines with oxygen to produce water. They are still too expensive for commercial use and remain experimental.

Ito stressed the environment was a pet theme for company founder Soichiro Honda, who repeatedly reminded workers the auto sector must share the responsibility for reducing emissions.

With files from CBC News