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6 Nanomaterials for Batteries
6.5.3 Research Progress
In order to speed up the commercialization of lithium-sulfur batteries and develop
secondary batteries with high energy density and long cycle life, the development of
lithium-sulfur batteries has reached an important stage, which has made a series of
major research progress. The results are summarized as follows:
The United States Sion Power Inc. is an earlier company in the research and
development of sulfur batteries. In July 2010, lithium-sulfur batteries and solar cells
were used on drones, and a record of 336 h of continuous flight was created. OXIS, a
British company established in 2004, dedicated to the development of lithium metal
secondary batteries, focusing on the high security and long cycle life of lithium-sulfur
batteries since its establishment. At present, the energy density of its next-generation
high-specific-energy lithium-sulfur battery has been higher than 300 Wh/kg. It is
hoped that lithium-sulfur batteries with twice the current energy storage capacity will
be developed and used in electric vehicles, aerospace, defense, and energy storage
systems in 2018. Domestic research on lithium-sulfur batteries is later than foreign
research, but with the support of national policies and funds, many achievements have
also been achieved. In 2008, the energy density of lithium-sulfur flexible packaging
batteries developed by Tsinghua University reached 246 Wh/kg. In 2012, the National
University of Defense Technology reported a lithium-sulfur soft pack battery that
attained 320–350 Wh/kg under 100% deep discharge for 100 cycles. In 2013, Dalian
Institute of Materials reported a lithium-sulfur soft-bag battery with a current density
of 350 Wh/kg after 40 cycles under 75% deep discharge. Then, it developed a 15
Ah lithium-sulfur battery with an energy density of more than 430 Wh/kg in August
2014.
The thermal research of lithium-sulfur batteries at home and abroad will certainly
increase the level of research and development, and the energy density of batteries will
continue to increase. The following describes the four aspects of the lithium-sulfur
battery cathode material, metal lithium negative electrode stability, and modification,
electrolyte solution, separator.
6.5.4 Cathode Material
Early sulfur cathode materials were simply a mixture of conductive agents, binders,
and elemental sulfur powders which is a macroscopic composite material. The shuttle
effect and the poor conductivity of the sulfur cathode have a greater influence on the
sulfur utilization and cycle stability. Therefore, in the past 20 years, researchers have
added some modified substances (carbon materials, polymers, or nano metal oxides)
to form nanocomposites with sulfur to boost the electrochemical performance of
lithium-sulfur batteries as well as the conductivity and stability of sulfur cathode
materials.
6 Nanomaterials for Batteries
6.5.3 Research Progress
In order to speed up the commercialization of lithium-sulfur batteries and develop
secondary batteries with high energy density and long cycle life, the development of
lithium-sulfur batteries has reached an important stage, which has made a series of
major research progress. The results are summarized as follows:
The United States Sion Power Inc. is an earlier company in the research and
development of sulfur batteries. In July 2010, lithium-sulfur batteries and solar cells
were used on drones, and a record of 336 h of continuous flight was created. OXIS, a
British company established in 2004, dedicated to the development of lithium metal
secondary batteries, focusing on the high security and long cycle life of lithium-sulfur
batteries since its establishment. At present, the energy density of its next-generation
high-specific-energy lithium-sulfur battery has been higher than 300 Wh/kg. It is
hoped that lithium-sulfur batteries with twice the current energy storage capacity will
be developed and used in electric vehicles, aerospace, defense, and energy storage
systems in 2018. Domestic research on lithium-sulfur batteries is later than foreign
research, but with the support of national policies and funds, many achievements have
also been achieved. In 2008, the energy density of lithium-sulfur flexible packaging
batteries developed by Tsinghua University reached 246 Wh/kg. In 2012, the National
University of Defense Technology reported a lithium-sulfur soft pack battery that
attained 320–350 Wh/kg under 100% deep discharge for 100 cycles. In 2013, Dalian
Institute of Materials reported a lithium-sulfur soft-bag battery with a current density
of 350 Wh/kg after 40 cycles under 75% deep discharge. Then, it developed a 15
Ah lithium-sulfur battery with an energy density of more than 430 Wh/kg in August
2014.
The thermal research of lithium-sulfur batteries at home and abroad will certainly
increase the level of research and development, and the energy density of batteries will
continue to increase. The following describes the four aspects of the lithium-sulfur
battery cathode material, metal lithium negative electrode stability, and modification,
electrolyte solution, separator.
6.5.4 Cathode Material
Early sulfur cathode materials were simply a mixture of conductive agents, binders,
and elemental sulfur powders which is a macroscopic composite material. The shuttle
effect and the poor conductivity of the sulfur cathode have a greater influence on the
sulfur utilization and cycle stability. Therefore, in the past 20 years, researchers have
added some modified substances (carbon materials, polymers, or nano metal oxides)
to form nanocomposites with sulfur to boost the electrochemical performance of
lithium-sulfur batteries as well as the conductivity and stability of sulfur cathode
materials.