03357nas a2200265   4500008004100000022001400041245011900055210006900174260000800243300001100251490000800262520246800270653001002738653001302748653002602761653002202787653002502809100002002834700002302854700002002877700002602897700002102923700001702944856013002961       2023                        eng d  a0167-273800aBenign strategy toward mesoporous carbon coated Sb nanoparticles: a high-performance Li-ion/Na-ion batteries anode0 aBenign strategy toward mesoporous carbon coated Sb nanoparticles  cAUG  a1162430 v3963 a<p>
	Antimony (Sb)-based anodes can offer excellent gravimetric capacity (-660 mAhg(1)) in lithium-ion/sodium-ion batteries (LIBs/SIBs) fabricated using carbonate-based electrolytes complexed with lithium/sodium salt. However, high first-cycle irreversible loss (35-40%) and gradual capacity fade (25-30%/cycle) originate from solid electrolyte interphase (SEI), and severe volumetric stress (-300%) associated with alloyed phase(s) impede reallife applications. Herein, we devise a benign strategy to develop mesoporous carbon coating onto antimony nanoparticles (Sb@C) based core-shell architecture for LIBs/SIBs anode. In particular, -30-50 nm thick mesoporous carbon spheres (-1 +/- 0.5 mu m) were obtained from resorcinol-formaldehyde (RF)-based polycondensation reaction by sol-gel chemistry engulfing Sb nanoparticles by suitably controlling Cetyltrimethylammonium bromide (CTAB)-induced steric stabilization and pH modulation during synthesis. The core-shell Sb@C helps faster Li+/Na+-ion migration preventing the structural collapse of Sb during electrochemical cycling and thereby improving the capacity fade. Electrochemical results demonstrate Sb@C can deliver a specific capacity of -536 mAhg(-1) and - 291 mAhg(-1) at 0.1C current rate in LIBs and SIBs, respectively, up to 200 cycles. Electrochemical impedance spectroscopy (EIS) indicates lower charge transfer (Rct) and SEI resistance (RSEI) of Sb@C cycled electrode than the bare Sb-NPs was the probable reason for improved Li/Na-ion storage in Sb@C anode. A detailed galvanostatic intermittent titration technique (GITT) and internal resistance measurements during 1st and 2nd cycles shed light on distinguishably different Li-ion/Na-ion storage behavior. The bulk Li+/Na+-ion diffusion coefficients found diminishes at reaction voltages (0.9 V/0.6 V for lithiation and 0.6 V/0.4 V for sodiation) corresponding with alloyed phase(s) concurrent with a drop in internal resistance at the quasi-opencircuit voltage (QOCV) during 1st and 2nd discharge cycle. On the contrary, de-alloying phenomena from the fully lithiated/sodiated phase(s) display an entirely opposite trend. The Li+ diffusion coefficient reaches minima at -1.1 V with a sudden jump in the internal resistance at QOCV during 1st and 2nd charge cycle. However, Na+ diffusion coefficient gradually drops along with a steep increase in the internal resistance, indicating partial Naion trapping and irreversible capacity loss.</p>
10aanode10aAntimony10alithium-ion batteries10amesoporous carbon10aSodium-ion batteries1 aDashairya, Love1 aChaturvedi, Vikash1 aKumar, Abhishek1 aMohanta, Tandra, Rani1 aShelke, Manjusha1 aSaha, Partha  uhttps://library.ncl.res.in/content/benign-strategy-toward-mesoporous-carbon-coated-sb-nanoparticles-high-performance-li-ionna01880nas a2200229   4500008004100000022001400041245009900055210006900154260000900223300001500232490000700247520113600254653001301390653001201403653002001415653001401435653002401449100001801473700002501491700001701516856011701533       2025                        eng d  a1439-423500aPushing the boundaries of pnictogen-bonding organocatalysis: a clash of Sb(III) versus Bi(III)0 aPushing the boundaries of pnictogenbonding organocatalysis a cla  cAUG   ae2025002650 v263 a<p>
	The sigma-hole-mediated noncovalent organocatalysis involving the pnictogen (Pn) elements has thus far been explored mostly from nitrogen to antimony, with antimony identified as the most effective catalyst. Herein, density functional theory calculations have been carried out to demonstrate that tri-aryl (Ar)-substituted bismuth(III) complexes can outperform their antimony counterparts in both anion (Cl-) binding and catalytic activity. Using a range of computational methods, a good correlation between the sigma-hole strength, chloride binding affinity, and the reaction barrier is established. Notably, the findings reveal that dispersion interactions are the dominant force in catalysts with weaker sigma-holes, while electrostatic interactions prevail in catalysts with stronger sigma-holes (for the anion abstraction step). In all cases, Bi(III) catalysts emerge as the winner over the Sb(III) analogues. Additionally, beyond the primary Pn. . .Cl interactions, several secondary interactions such as Cl. . .H/F-C(Ar) and Cl-. . . H-C(Si-TBS) also play a significant role in stabilizing the transition states.</p>
10aAntimony10aBismuth10aorganocatalysis10apnictogen10asigma (sigma) holes1 aSharma, Jyoti1 aDash, Soumya, Ranjan1 aVanka, Kumar  uhttps://library.ncl.res.in/content/pushing-boundaries-pnictogen-bonding-organocatalysis-clash-sbiii-versus-biiii