Date: Dec 6, 2017
When it is cold in winter, cars tend to have starting problems. This is not much better with electric cars, which inevitably lose capacity of their rechargeable lithium-ion batteries at freezing temperatures. Now, Chinese scientists have offered a strategy to avoid plunging battery kinetics. In a study published in the journal Angewandte Chemie, they designed a battery system with a cold-enduring hard-carbon anode and a powerful lithium-rich cathode, with the important initial lithiation step integrated.
“Non-graphitizable” or “hard” carbon is a promising, low-cost anode material in battery technology. Even at low temperatures, it exhibits fast intercalation kinetics of lithium ions. During charging/discharging of a battery cell, lithium ions migrate from the cathode through an electrolyte to the anode and vice versa. If the anodic material, which is often graphite, contains prestored lithium, the volume change by the incoming lithium ions is leveled out to ensure a longer cell life and faster charge/discharge kinetics. Prelithiated hard carbon has been proven as a robust material in lithium-ion capacitors. However, the prelithiation process, which involves a pure lithium electrode, is complicated and expensive. Alternative prelithiation strategies are therefore favored by Yonggang Wang and his team at Fudan University, Shanghai, China.
