Lithium batteries will produce dendrites during use. Dendritic fracture will not only cause battery capacity to decay, but also shorten the life span. It may also pierce the diaphragm to short-circuit the battery and cause fire safety. Professor Nan Jiakai, Professor Liang Yongjie and Prof. Chen Yongsheng and Jiangsu Normal University Lai The super-group cooperated to propose a new optimization strategy to solve this problem. A silver nanowire-graphene three-dimensional porous carrier with multi-stage structure was successfully prepared, and metal lithium was supported as a composite anode material. This carrier can inhibit lithium dendrites. Produced, which can achieve ultra-high-speed battery charging, is expected to significantly extend the 'lifetime' of lithium batteries. The research results were published in the latest issue of Advanced Materials.
In recent years, many countries in the world have made important breakthroughs in the design and synthesis of lithium anode materials, but still can not inhibit the problem of dendrites and electrode volume expansion of lithium metal under high current density charge and discharge, so the length of lithium batteries Life, large capacity 'fast charge fast release' is still insurmountable.
'The deposition of metallic lithium into a porous current collector with a three-dimensional network structure to construct a metallic lithium composite anode material is one of the effective ways to solve the above difficulties. 'Liang Jiajie said. Based on this understanding, the research group first proposed to achieve ultra-high current. The ideal metal lithium anode three-dimensional carrier material selection and optimization strategy for density and ultra-long cycle life. They use the graphene macroscopic three-dimensional network as the mechanical skeleton, and the silver nanowire two-dimensional network as the conductive structure, which is compatible with industrial production through low cost. Coating-cold-drying method, preparing silver nanowires with multi-stage structure - graphene three-dimensional porous carrier, and supporting metal lithium as metal lithium composite anode material.
After testing, the specific capacity of the metal lithium composite anode material can reach 2573 mAh / g; in the symmetrical battery test, for the first time, it is repeatedly charged and discharged at a very high current density of 40 mAh/cm 2 for more than 1000 weeks, and the overpotential is less than 120 mV. It can be seen by electron microscopy that the multi-level three-dimensional structure carrier can successfully inhibit the growth of lithium dendrites and the volume change of the electrode in the lithium metal anode even under the cyclic conditions of maximum current charge and discharge.
