Nitrogen- and TiN-modified Li4Ti5O12: one-step synthesis and electrochemical performance optimization
MetadataShow full item record
It is believed that a TiN coating can increase the electrical conductivity, and consequently the performance, of an electrode. In this work, a simple one-step synthesis of nitrogen- and TiN-modified Li4Ti5O12, i.e. solid-state reaction of Li2CO3 and TiO2 anatase in an ammonia-containing atmosphere, is introduced. The reducing ammonia atmosphere could cause the partial reduction of Ti4+ to Ti3+ and the doping of nitrogen into the Li4Ti5O12 lattice, in addition to the formation of the TiN phase. By controlling the ammonia concentration of the atmosphere and using a slight Ti excess in the reactants, Li4Ti5O12, nitrogen-doped Li4Ti5O12, or TiN-coated nitrogen-doped Li4Ti5O12 were obtained. Both the electrical conductivity and the TiN thickness were closely related to the ammonia concentration in the atmosphere. Synthesis under reducing atmosphere also resulted in powders with a different plate shape particulate morphology from that synthesized in air, and such plate-shape powders had an ultrahigh tap density of ~1.9 g cm−3. Interestingly, the formation of TiN was not beneficial for capacity improvement due to its insulation towards lithium ions, unlike the nitrogen doping. The sample prepared under 3% NH3–N2, which was free of TiN coating, showed the best electrode performance with a capacity of 103 mA h g−1 even at 20 C with only 3% capacity decay after cycling 100 times.
Showing items related by title, author, creator and subject.
Activation of photocatalytic water oxidation on N-doped ZnO bundle-like nanoparticles under visible lightZong, X.; Sun, C.; Yu, H.; Chen, Z.; Xing, Z.; Ye, D.; Lu, G.; Li, Xin Yong; Wang, L. (2013)Nitrogen-doped ZnO bundle-like nanoparticles were prepared by heating ZnOHF precursor at different temperatures under an ammonia atmosphere. ZnOHF gradually transformed to N-ZnO with the increase of the heating temperature, ...
Facile single-step ammonia heat-treatment and quenching process for the synthesis of improved Pt/N-graphene catalystsXiong, B.; Zhou, Y.; O'Hayre, R.; Shao, Zongping (2013)In this work, we present a facile route to prepare electrocatalysts for methanol oxidation. The catalystsynthesis route involves the simultaneous reduction and nitrogen doping of graphene oxide (GO) along with the reduction ...
Effects of niobium doping site and concetration on the phase structure and oxygen permeability of Nb-substituted SrCoOx oxidesZhang, K.; Ran, R.; Shao, Zongping; Zhu, Z.; Jin, Y.; Liu, Shaomin (2010)Niobium doping effect on phase structure, phase stability and electrical conductivity of SrCoOx oxides and oxygen permeability of the corresponding membranes were systematically investigated. Niobium was successfully ...