Carbon materials

Abstract

There is described a carbon material comprising sp 2 and sp 3 hybridised carbon. Also described is a method of making a carbon material the method comprising: exposing a substrate to a flux of at least 10 11 carbon ions per cm 2 of substrate per 1 ms, a majority of the carbon ions having a kinetic energy of at least 10 eV. Further, electrodes comprising the carbon material are described. The electrodes may operate as an anode in Li ion battery characterised with improved specific capacity and operation life-time.

What is claimed is: 
     
         1 . A carbon material formed by exposing a substrate to a flux of at least 10 11  carbon ions per cm 2  of substrate per 1 ms while the substrate is at a temperature of less than 60° C., a majority of the carbon ions having a kinetic energy of at least 10 eV to provide a carbon material comprising sp 2  and sp 3  hybridized carbon. 
     
     
         2 . The carbon material of  claim 1 , wherein the carbon material has a hierarchical porosity to provide a specific lithium storage capacity of at least 400 mAh/g. 
     
     
         3 . The carbon material of  claim 1 , wherein the percentage of sp 2  type carbon is at least 25 w % based on the total weight of the material. 
     
     
         4 . The carbon material of  claim 1 , wherein the percentage of sp 3  type carbon is at least 20 w % based on the total weight of the carbon material. 
     
     
         5 . The carbon material of  claim 1 , comprising at least one area with a plurality of regularly arranged, graphene-like layers of carbon and the at least one area is embedded in amorphous carbon. 
     
     
         6 . The carbon material of  claim 5 , wherein an inter-layer spacing between individual layers in the plurality of layers is greater than 0.335 nm. 
     
     
         7 . The carbon material of  claim 1 , wherein the carbon material has an electrical conductivity of at least 1 S/m. 
     
     
         8 . The carbon material of  claim 1 , wherein the carbon material has an initial specific lithium storage capacity of at least 1000 mAh/g at a first charge cycle. 
     
     
         9 . The carbon material of  claim 1 , wherein the carbon material has a surface area of at least 1000 m 2 /g. 
     
     
         10 . The carbon material of  claim 1 , wherein the carbon material comprises from 0.1 w % to 30 w % of one or more additives or dopants, the one or more additives or dopants comprising an element selected from the group consisting of Si, P, Fe, Cu, Li, Al, N, O, S, P, B, Ti, Co, Ni, Na, K, and combinations thereof. 
     
     
         11 . The carbon material of  claim 10 , wherein the one or more additives or dopants are either co-deposited with the carbon or incorporated into the carbon material as a plurality of particles or layers. 
     
     
         12 . The carbon material of  claim 1 , wherein the specific lithium storage capacity after 200 charge/discharge cycles is at least 400 mAh/g. 
     
     
         13 . The carbon material of  claim 1 , wherein the carbon material is formed by physical vapor deposition (PVD). 
     
     
         14 . The carbon material of  claim 1 , wherein the hierarchical porosity comprises a first set of grains having a size of between 10 nm and 100 nm, a second set of grains having a size of between 100 nm and 1000 nm, and a third set of grains having a size of greater than 1 μm. 
     
     
         15 . The carbon material of  claim 1 , wherein the percentage of sp 2  type carbon is between 54 w % and 59 w %, and the percentage of sp 3  type carbon is between 24 w % and 31 w %. 
     
     
         16 . The carbon material of  claim 1 , wherein the percentage of sp 2  type carbon is between 79 w % and 81 w %, and the percentage of sp 3  type carbon is between 7 w % and 9 w %. 
     
     
         17 . A method of making a carbon material, the method comprising:
 exposing a substrate to a flux of at least 10 11  carbon ions per cm 2  of substrate per 1 ms while the substrate is at a temperature of less than 60° C., a majority of the carbon ions having a kinetic energy of at least 10 eV to provide a carbon material comprising sp 2  and sp 3  hybridized carbon.   
     
     
         18 . The method of  claim 17 , wherein the sp 2  and sp 3  hybridized carbon have a hierarchical porosity to provide a specific lithium storage capacity of at least 400 mAh/g. 
     
     
         19 . The method of  claim 17 , wherein the percentage of sp 2  type carbon is at least 25 w % based on the total weight of the material and the percentage of sp 3  type carbon is at least 20 w % based on the total weight of the carbon material. 
     
     
         20 . The method of  claim 17 , wherein the carbon material comprises at least one area with a plurality of regularly arranged, graphene-like layers of carbon and the at least one area is embedded in amorphous carbon. 
     
     
         21 . The method of  claim 17 , wherein the flux is provided by a virtual cathode deposition (VCD) process. 
     
     
         22 . The method of  claim 17 , further comprising co-depositing one or more dopants or additives to form part of the carbon material or incorporating the dopant or additives into the carbon material as particles or layers. 
     
     
         23 . The method of  claim 17 , further comprising separating the carbon material from the substrate to provide a free-standing carbon material film. 
     
     
         24 . The method of  claim 17 , wherein the carbon material is deposited on the substrate without any binders to adhere the carbon to the substrate. 
     
     
         25 . The method of  claim 17 , wherein the flux is pulsed with a pulsing frequency of between 1 Hz and 20,000 Hz, a pulse duration of between 0.1 μs and 1000 μs, and a total energy per pulse of greater than 2.5 J. 
     
     
         26 . The method of  claim 17 , wherein the flux is provided in a plurality of pulses such that the carbon ions contact the substrate in less than 50 μs. 
     
     
         27 . The method of  claim 26 , wherein a relaxation time between each of the plurality of pulses is at least 100 μs.