ARCI Researchers says coating carbon on lithium metal oxide electrode doubles the battery life

Carbon Coating, Doubles life of lithium-ion batteries: ARCI Researchers discovered a low-cost method for coating carbon on lithium metal oxide electrodes used in lithium-ion batteries. Because of the protective carbon covering, the life of lithium-ion batteries made with these electrode materials is expected to be doubled.

The most popular power source for electric vehicles is lithium-ion batteries. However, the adoption of gasoline-based vehicles into daily uses demands a significant increase in service life, costs and kilometres per charge.

Cathode, anode and electrolyte are the active components of lithium-ion batteries. Lithium metal oxides or lithium metal phosphates are being utilised as cathodes in Li-ion batteries, whereas commercial graphite is used as an anode. A lithium salt dissolved in organic solvents is the electrolyte.

The lithium-ion battery’s capacity influences the electric vehicle’s mileage. The number of charge cycles influences the battery life before the capacity is reduced to 80%. Carbon is the ideal coating material to increase the cyclic stability of active materials since it is inert to most chemicals and stable under the operating window.

Carbon coating on active materials has the potential to quadruple the lifetime of lithium-ion batteries. Covering carbon on lithium metal oxide, on the other hand, is extremely tough due to the complexity associated with coating carbon during the production of lithium metal oxide material in a single step.

Researchers at the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), an autonomous institute of the Department of Science and Technology developed a technique for coating carbon in situ on lithium transition metal oxides in a single step while synthesising the oxide itself to address this issue.

Carbon is usually deposited on oxide materials in a second process, which is inefficient and costly. Even when heat-treated in the air during solid-state synthesis, the ARCI technique traps a carbon precursor in between the transition metal hydroxide layers to limit the interaction with oxygen. This method resulted in a uniform carbon coating on lithium transition metal oxides —LiNi0.33Mn0.33Co0.33O2 (NMC111).

The lithium-ion cells built with carbon-coated NMC111 have electrochemical performance comparable to commercial lithium-layered oxide cathodes.

Superior cyclic stability is proven with an optimal carbon thickness that matches commercial samples of the carbon-coated product with a retention capacity of over 80% after 1000 load/discharge cycles.

The electrochemical performance is expected to increase further if the lab-scale batch method is replaced with a continuous process, allowing the technology to be commercially feasible, says ARCI experts.