This article doesn't actually get into what the idea is. Instead, it explains the entire history of the world hoping you don't notice the idea is missing
"Although Goodenough will not spell out his precise new idea, he thinks he is on to something."
I got that impression too, but it does say "But the path he has chosen involves one of the toughest problems in battery science, which is how to make an anode out of pure lithium or sodium metal."
I suppose that implies he's trying to make an anode out of pure lithium or sodium, but you never know with science journalism.
"Although Goodenough will not spell out his precise new idea, he thinks he is on to something."