Pressure-Induced Topochemical Polymerization toward Advanced Energetic Materials

Pressure produces closely packed,high-density materials,thereby providing a promising strategy to obtain high-energy-density materials.However,new phases or structures of energetic materials at high pressure are often not quenchable under ambient conditions.In this work,high-pressure topochemical methodology is first introduced for the preparation of stable energetic materials under ambient conditions.A pressure-induced polymerizable energetic material named PIP-1 is designed and prepared.The experimental measurements demonstrate that the polymerization of PIP-1 is caused by the breakage of C≡C bonds and the generation of C=C bonds.In accord with the experimental results,density functional theory calculations further revealed that the monomer PIP-1 is polymerized to generate 1D PIP-1 tape,and the density of polymerized PIP-1 is increased by 4.9%upon decompression.The successful realization of high-energy-density structure using high pressure showcases a new design strategy for advanced polymerizable energetic materials.

Identifying quasi-2D and 1D electrides in yttrium and scandium chlorides via geometrical identification

Developing and understanding electron-rich electrides offers a promising opportunity for a variety of electronic and catalytic applications.Using a geometrical identification strategy,here we identify a new class of electride material,yttrium/scandium chlorides Y(Sc)_(x)Cl_(y)(yx<2).Anionic electrons are found in the metal octahedral framework topology.The diverse electronic dimensionality of these electrides is quantified explicitly by quasi-two-dimensional(2D)electrides for[YCl]^(+)∙e−and[ScCl]^(+∙)e−and one-dimensional(1D)electrides for[Y_(2)Cl_(3)]^(+)∙e−,[Sc_(7)Cl_(10)]^(+)∙e−,and[Sc5Cl8]2+∙2e−with divalent metal elements(Sc^(2+):3d^(1) and Y^(2+):4d^(1)).The localized anionic electrons were confined within the inner-layer spaces,rather than inter-layer spaces that are observed in A_(2)B-type 2D electrides,e.g.Ca_(2)N.Moreover,when hydrogen atoms are introduced into the host structures to form YClH and Y2Cl3H,the generated phases transform to conventional ionic compounds but exhibited a surprising reduction of work function,arising from the increased Fermi level energy,contrary to the conventional electrides reported so far.Y_(2C)l_(3) was experimentally confirmed to be a semiconductor with a band gap of 1.14 eV.These results may help to promote the rational design and discovery of new electride materials for further technological applications.