Application of titanium-based compounds in lithium-sulfur batteries

Application of titanium-based compounds in lithium-sulfur batteries
The development of new high-performance energy storage devices is a research focus and focus in the field of energy and materials. Lithium-ion batteries are currently one of the more mature electrochemical energy storage systems. However, due to the limited theoretical specific capacity of the positive and negative materials, their energy density cannot continue to increase, and it is difficult to meet the large-scale utilization of wind and solar energy and other renewable energy and electric power. The needs of the rapid development of the automotive industry. Lithium-sulfur batteries with low-cost sulfur as the positive electrode and lithium metal as the negative electrode have high theoretical energy density and are one of the next-generation energy storage devices with practical prospects, but their commercial applications still face many challenges.
In recent years, lithium-sulfur batteries have attracted people's attention for their super-high theoretical energy density. However, limited by the problems of sulfur insulation, polysulfide shuttle effect, and positive electrode volume expansion, the market application of lithium-sulfur batteries has not yet been realized.
Because the lithium-sulfur battery has a very high specific capacity and theoretical energy density (about 1675 mAh g-1 and 2600 Wh kg-1), and the active material sulfur also has the advantages of large energy density, abundant raw material reserves, low cost, and environmental friendliness. Therefore, it has become one of the more promising high-energy-density systems than commercial lithium-ion batteries (LIB). However, the positive side of lithium-sulfur batteries also has serious problems such as poor conductivity of sulfur, large volume expansion of active materials during discharge, and soluble polysulfide lithium compounds (LiPSs, Li2Sn: 3n≤8) that are prone to the "shuttle effect". As a result, the cycle stability of the lithium-sulfur battery deteriorates and the coulombic efficiency decreases. To solve the problems of lithium-sulfur batteries and effectively improve their electrochemical performance, this thesis starts from the aspects of self-supporting sulfur-based composite materials, membrane modification coating materials, and new cathode materials, respectively, using hydrothermal methods to prepare graphene. /Nickel hydroxide self-supporting sulfur-based composite materials, graphene/nickel hydroxide composite materials with different mass ratios for modified diaphragms, Mn-doped nickel hydroxide sulfur-based materials, and the electrochemical performance of the above materials on lithium-sulfur batteries At the same time, discuss its mechanism of action.
The development and application of lithium secondary batteries are deeply advancing a revolution in the energy field. The era of "oil-burning driving and coal-fired power generation" will end shortly. Lithium-ion batteries have become the "energy source" of people's daily life. However, the theoretical specific capacity and specific energy of traditional lithium-ion batteries are low, and it is difficult to meet the increasing energy demand of human society. With the rapid development of smart electronic equipment, zero-emission electric vehicles, and low-cost and high-efficiency electrical energy storage systems, people have put forward higher requirements for the energy density, cycle life, and safety performance of energy storage batteries.
 

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