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Biomass carbon-encapsulated transition metal sulfides (TMSs) as anodes for enhanced lithium-ion storage have recently been one hot topic in sustainable development. Herein, three Co9S8-based biomorphic materials were prepared by simple immersion of discarded scallion roots in Co-(NO3)2 solution, followed by in situ calcination and sulfidation reactions under different atmospheres. Among them, the Co9S8/GC-1 nanocomposite is formed by the cross-linkage of 43 wt % biomass-derived graphitized carbon (GC) and small-sized nanoparticles, which possess multilevel mesoporous distribution and a large specific surface area (109.3 m2·g–1). Such unique structure not only shortens the migration path of Li+ ions and promotes the rapid penetration of electrolyte to form a stable solid electrolyte interphase (SEI) membrane but also inhibits the agglomeration of Co9S8 nanoparticles and alleviates their volume expansion, which in turn ensures the structural stability of the electrode material and provides good pseudocapacitance behavior. As an anode for lithium-ion batteries (LIBs), the discharge capacity of the Co9S8/GC-1 electrode is 381 mA h g–1 at 5 A g–1. Especially at 1 A g–1, its capacity can still be stabilized to 471.3 mA h g–1 over 2000 cycles. This indicates that the Co9S8/GC-1 nanocomposite has good capacity retention and long-cycling performance, further being applied as a candidate anode for LIBs. [ABSTRACT FROM AUTHOR]

Transition-metal sulfides as anodes for lithium-ion batteries (LIBs) have attracted more attention due to their good conductivity and high capacity. However, relevant lithium storage at low temperatures has been less reported so far. Herein, willow catkins (WC) as biotemplate were simply soaked in cobalt salt solution, and the obtained precursors were in situ carbonized, calcined, and sulfurated under different atmospheres to generate two biomorphic Co9S8-based tubes. The biomass-derived carbon (BC) decorated Co9S8 nanocomposite (Co9S8/BC) shows that Co9S8 nanoparticles (ave. 30 nm) are homogeneously embedded in biocarbon tubes, which can effectively relieve the volume expansion of Co9S8 nanoparticles. As anode for LIBs, the Co9S8/BC electrode exhibits good rate performance (437 mA h g–1, 5 A g–1) and long-cycling stability (510.3 mA h g–1, 2000 cycles, 1 A g–1) at room temperature. Especially at 0 and −20 °C, the capacities can separately remain at 397.2 and 197.1 mA h g–1 after 150 cycles at 1 A g–1. The excellent electrochemical performance is mainly attributed to the synergistic effect of the unique microstructure and biomass-derived graphitic carbon, which can offer more active sites, enhance the conductivity, and relieve the volume expansion of the electrode material. [ABSTRACT FROM AUTHOR]

It is of great practical significance to develop portable and conductometric sensors for detecting flammable and explosive high-energy n-pentanol vapor. In view of the very few reports on metal oxide-based n-pentanol sensors, herein, biomorphic ZnO nanotubes were synthesized through a zinc salt impregnation–calcination method using poplar branch as a biotemplate. The multistage porous ZnO-500 tube arrays obtained from calcination at 500 °C are cross-linked by small-size nanoparticles, which are beneficial to the rapid adsorption and diffusion of n-pentanol vapor with a long alkyl chain. A ZnO-500-based sensor presents high and fast response (S = 221.0; Tres = 4 s) to 100 ppm n-pentanol vapor at 252 °C, as well as a low detection limit (100 ppb) and a wide linear relationship. Under the synergistic effect of inherent characteristics of the biomorphic structure and biotemplate imprinting, the above comprehensive gas-sensing indicators are significantly superior to those of the reported metal oxide-based sensors. Thus, the porous ZnO-500 nanomaterials prepared by a simple, low-cost, and controllable biotemplate method have the potential to be fabricated as candidates for the rapid and accurate detection of trace amounts of n-pentanol. [ABSTRACT FROM AUTHOR]