Tin nanoparticles and methodology for making same

Abstract

A method of preparing tin (Sn) nanoparticles based on a bottom-up approach is provided. The method includes combining a first solution comprising Sn ions with a second solution comprising a reducing agent. After the combination, the Sn ions and the reducing agent undergo a reaction in which at least some of the Sn ions are reduced to Sn nanoparticles. The first solution comprises a tin salt dissolved in a solvent; the second solution comprises an alkali metal and naphthalene dissolved in a solvent; and the combined solution further comprises a capping agent that moderates a growth of aggregates of the Sn nanoparticles.

1 . A method comprising:
 forming a reaction mixture comprising a solution of a tin salt, a reducing agent, and a capping agent; and   reducing at least a portion of the tin salt in the presence of the reducing agent and the capping agent to form aggregates of tin nanoparticles;   wherein the capping agent moderates a growth of the aggregates of tin nanoparticles, the capping agent comprising a functional group selected from the group consisting of an amine, a phosphine, a thiol, and a carboxylate.   
     
     
         2 . The method of  claim 1 , wherein forming a reaction mixture comprises combining a first solution comprising the tin salt with a second solution comprising the reducing agent. 
     
     
         3 . The method of  claim 2 , wherein the capping agent is present in the first solution. 
     
     
         4 . The method of  claim 1 , wherein the reducing agent comprises an alkali metal and naphthalene. 
     
     
         5 . The method of  claim 1 , wherein the reducing agent comprises sodium borohydride or butyl lithium. 
     
     
         6 . The method of  claim 1 , wherein the tin salt comprises tin (II) chloride or tin (IV) chloride. 
     
     
         7 . The method of  claim 1 , wherein the capping agent is present in the reaction mixture before reducing the tin salt takes place. 
     
     
         8 . The method of  claim 1 , wherein the tin nanoparticles further comprise a tin oxide (SnO 2 ) shell at least partially surrounding the tin nanoparticles. 
     
     
         9 . The method of  claim 1 , wherein a median size of the tin nanoparticles ranges from about 20 nm to about 100 nm. 
     
     
         10 . The method of  claim 1 , wherein a median size of the tin nanoparticles ranges from about 100 nm to about 500 nm. 
     
     
         11 . A method comprising:
 forming a reaction mixture comprising a solution of a tin salt, a reducing agent, and a capping agent;   reducing at least a portion of the tin salt in the presence of the reducing agent and the capping agent to form aggregates of tin nanoparticles; and   allowing the tin nanoparticles to at least partially oxidize to form a tin oxide (SnO 2 ) shell at least partially surrounding the tin nanoparticles;   wherein the capping agent moderates a growth of the aggregates of tin nanoparticles, the capping agent comprising a functional group selected from the group consisting of an amine, a phosphine, a thiol, and a carboxylate.   
     
     
         12 . The method of  claim 11 , wherein forming a reaction mixture comprises combining a first solution comprising the tin salt with a second solution comprising the reducing agent. 
     
     
         13 . The method of  claim 12 , wherein the capping agent is present in the first solution. 
     
     
         14 . The method of  claim 11 , wherein the reducing agent comprises an alkali metal and naphthalene. 
     
     
         15 . The method of  claim 11 , wherein the capping agent is present in the reaction mixture before reducing the tin salt takes place. 
     
     
         16 . A battery comprising one or more anode electrodes, the one or more anode electrodes comprising aggregates of tin nanoparticles prepared by the method of  claim 1 . 
     
     
         17 . The battery of  claim 16 , wherein the battery is a lithium battery. 
     
     
         18 . The battery of  claim 16 , wherein the one or more anode electrodes further comprise carbon nanotubes. 
     
     
         19 . The battery of  claim 16 , wherein the tin nanoparticles further comprise a tin oxide (SnO 2 ) shell at least partially surrounding the tin nanoparticles. 
     
     
         20 . The battery of  claim 16 , wherein a median size of the tin nanoparticles ranges from about 20 nm to about 100 nm.