Hydrothermal Pretreatment of Lignocellulosic Materials for Improving Bioethanol Production

With the continued depletion of non-renewable energy resources,it is essential to seek new methods of harnessing clean and renewable energy.In this regard,second-generation bioethanol derived from lignocellulosic biomass has attracted increasing attention in recent years.The choice of the pretreatment method of lignocellulose is critical to the subsequent bioconversion processes.Compared with other conventional chemical pretreatment methods,hydrothermal pretreatment is a simple,low-cost,and economically feasible process that requires water as the only reagent.This paper reviews the research efforts that have been made toward hydrothermal pretreatment of lignocellulosic biomass and focuses on the transformations involving cellulose,hemicellulose,and lignin during this process.

Synergistic modulation of Li nucleation/growth enabled by CNTswrapped lithiophilic CoP/Co_(2)P decorated hollow carbon polyhedron host for stable lithium metal anodes

Infinite volume expansion and uncontrolled lithium dendrite growth are the main bottlenecks that greatly hinder the commercial application of lithium metal anodes.Herein,derived from zeolitic imidazolate framework(ZIF)-67,carbon nanotubes(CNTs)-wrapped and CoP/Co_(2)P uniformly distributed nitrogen-doped hollow porous polyhedron carbon(CNT-CoP@NC)is elaborately designed as lithium metal host.A hybrid of N-doping and metallic phosphides modifications improves the lithiophilicity and reduces the nucleation barrier,consequently leading to homogeneous nucleation and smooth deposition of metallic lithium,thus suppresses the growth of Li dendrites.Meanwhile,self-generated CNTs arrays efficiently reduce the local current density.Moreover,the reduced lithium is preferentially deposited into the hollow structure of CNT-CoP@NC and then filled the voids among the CNT-CoP@NC particles.This all-pervasive Li plating design can not only alleviate the volume effect,but also maximize the anode space utilization.Benefiting from these synergistic modulations,even with an ultra-thin(7.2μm)anode layer of CNT-CoP@NC host,a high Coulombic efficiency for more than 400 cycles and an extended lifespan of 1,700 h under 1 mA·cm^(−2)can be achieved.When paired with a competitive high mass loading(17.1 mg·cm^(−2))LiFePO4 cathode,a superb cycling stability(126.7 mAh·g^(−1)over 550 cycles)is recorded at 1 C.

Li-Zn alloy patch for defect-free polymer interface film enables excellent protection effect towards stable Li metal anode

Constructing a smart polymer film with favorable lithium(Li)transport capability and mechanical flexibility for suppressing Li dendrite growth is an effective strategy.Unfortunately,the porosity and the swelling of the polymer membrane cannot completely prevent liquid electrolyte from sweeping through the artificial protection film,severely deteriorating the cyclic performance.Herein,we propose a defectfree hybrid film that consists of Li+conductive lithium polyacrylate(LiPAA)polymer interface layer and Li-Zn alloy patch to tackle the critical problems of traditional polymer composite passivation film.The pinhole leaks of the polymer matrix are self-filled by Li-Zn alloy patches,enhancing the integrity of LiPAA film.Consequently,a defect-free hybrid film is nailed flat against the Li metal anode,exhibiting extraordinary stability in the liquid electrolyte and enabling perfect protection effect.This facile strategy produces a promising anode for next generation Li batteries.

Li_(x)Cu alloy nanowires nested in Ni foam for highly stable Li metal composite anode

Porous metal architectures are widely adopted as three-dimensional conducting scaffolds for constructing Li metal composite anodes,whereas their macropores hinder their practical application due to limited surface area and large pore size of few hundred micrometers.In this work,a network of Li_(x)Cu solid solution alloy nanowires is in situ formed via infiltrating molten Li-Cu alloy into Ni foam and subsequent cooling treatment,whereby a three-component composite anode consisting of Li metal,Li_(x)Cu alloy,and Ni foam is fabricated.The Li_(x)Cu nanowires nested as secondary frame split the macropores into micropores,enlarging the active surface area and inducing uniform Li deposition significantly.The lithiophilicity of the alloy wires and the shrunken void size built by the hierarchical architecture can further tune the nucleation and growth behavior of Li.The multiscale synergetic effect between the primary and secondary scaffold guarantees the composite anode sheet with extraordinarily long-term cycling stability even under high current rates.

Li-Ca Alloy Composite Anode with Ant-Nest-Like Lithiophilic Channels in Carbon Cloth Enabling High-Performance Li Metal Batteries

Constructing a three-dimensional(3D)multifunctional hosting architecture and subsequent thermal infusion of molten Li to produce advanced Li composite is an effective strategy for stable Li metal anode.However,the pure liquid Li is difficult to spread across the surface of various substrates due to its large surface tension and poor wettability,hindering the production and application of Li composite anode.Herein,heteroatomic Ca is doped into molten Li to generate Li-Ca alloy,which greatly regulates the surface tension of the molten alloy and improves the wettability against carbon cloth(CC).Moreover,a secondary network composed of CaLi2 intermetallic compound with interconnected ant-nest-like lithiophilic channels is in situ formed and across the primary scaffold of CC matrix by infiltrating molten Li-Ca alloy into CC and then cooling treatment(LCAC),which has a larger and lithiophilic surface to enable uniform Li deposition into interior space of the hybrid scaffold without Li dendrites.Therefore,LCAC exhibits a long-term lifespan for 1100 h under a current density of 5 mA cm^(-2)with fixed areal capacity of 5 mAh cm^(-2).Remarkably,full cells paired with practical-level LiFePO4 cathode of 2.45 mAh cm^(-2)deliver superior performance.