Just for notebook computers now, enough of these -as in the over 6,000 such cells that propel a Tesla, could have a profound short-term effect on our hopes for electric flight. The 18650 (18 mm in diameter, 65 mm long) cells by Panasonic are the first to offer a silicon alloy anode, a commercial verification of the research Drs. Cui and Cho have been performing. Panasonic promises 4.0 Amp hours capacity, almost 30-percent more than current lithium cells of the same size. This allows a notebook battery pack almost half the size of one using graphite anode cells. The good news is balanced by the fact that the Si-based cell, at 54 grams each, weighs 10 grams more than the existing model. According to Nikkei Electronics Asia, “The initial target application will be notebook PCs, but a source at the firm comments ‘the ultimate target is vehicles.’ For vehicular applications, weight will be a key issue…. The weight energy density …