Nanocomposite protective coatings for battery anodes
Modified surfaces on metal anodes for batteries can help resist formation of malfunction-inducing surface defects. The modification can include application of a protective nanocomposite coating that can inhibit formation of surface defects. such as dendrites, on the anode during charge/discharge cycles. For example, for anodes having a metal (M′), the protective coating can be characterized by products of chemical or electrochemical dissociation of a nanocomposite containing a polymer and an exfoliated compound (M a ′M b ″X c ). The metal, M′, comprises Li, Na, or Zn. The exfoliated compound comprises M′ among lamella of M b ″X c , wherein M″ is Fe, Mo, Ta, W, or V, and X is S, O, or Se.
1. A protective coating on battery anodes comprising a metal (M′), wherein M′ is Li, Na, or Zn, the protective coating characterized by products of chemical or electrochemical dissociation of a nanocomposite containing a polymer and an exfoliated intercalation compound (M a ′M b ″X c ) comprising M′ among lamella of M b ″X c , wherein M″ is Fe, Mo, Ta, W, or V, and X is S, O, or Se.
2. The protective coating of claim 1 , wherein the products of electrochemical dissociation comprise at least one of M r ′X s , M″/M t ′, M u ″, and X v in a matrix of the polymer.
3. The protective coating of claim 1 , further comprising graphene in the matrix of the polymer.
4. The protective coating of claim 1 , wherein the nanocomposite has a substantially disordered arrangement of M b ″X c lamella.
5. The protective coating of claim 1 , wherein the nanocomposite has a substantially layered arrangement of M b ″X c lamella.
6. The protective coating of claim 1 , wherein the polymer comprises polyether functionality.
7. The protective coating of claim 6 , wherein the polymer comprises polyethylene oxide (PEO).
8. A battery having an anode comprising Li and a protective coating over the anode, the protective coating characterized by products of anodic reduction of a nanocomposite containing a polymer and an exfoliated intercalation compound (Li a MoS 2 ) comprising Li among lamella of MoS 2 , the products of anodic reduction comprising at least one of Li 2 S, S 8 , Mo, Li/Mo, and polysuflide in a matrix of the polymer.
9. The battery of claim 8 , further comprising graphene in the matrix of the polymer.
10. A method of preparing a protective coating for battery anodes comprising a metal (M′), wherein M′ is Li, Na, or Zn, the method characterized by the steps of:
Exfoliating an intercalation compound (M a ′M b ″X c ) in a solution to yield a colloid comprising substantially separated lamella of M b ″X c , wherein M″ is Fe, Mo, Ta, W, or V, and X is S, O, or Se;
Adsorbing a polymer to the lamella of M b ″X c in the colloid;
Forming a nanocomposite by drying the colloid, the nanocomposite comprising the polymer and M′ among lamella of M b ″X c ;
Applying the nanocomposite to surfaces of the anode; and
Chemically or electrochemically dissociating the nanocomposite to yield a product comprising at least one of M r ′X s , M″/M t ″, M u ″, and X v in a matrix of the polymer.
11. The method of claim 10 , wherein the colloid further comprises graphene.
12. The method of claim 10 , further comprising reacting X y with dendrites comprising M′ formed on surfaces of the battery anode.
13. The method of claim 10 , wherein said forming further comprises forming a nanocomposite having a substantially disordered arrangement of lamella of M b ″X c .
14. The method of claim 10 , wherein said forming further comprises forming a nanocomposite having a substantially layered arrangement of lamella of M b ″X c .
15. The method of claim 10 , wherein the polymer comprises polyether functionality.
16. The method of claim 15 , wherein the polymer comprises PEO.
17. The method of claim 10 , wherein M′ is Li, M a ′M b ″X c is Li a MoS 2 , M b ″X c is MoS 2 , M r ′X s is Li 2 S, M″/M t ′ is Mo/Li t , M u ″ is Mo u , and X v is S 8 or polysulfide.
18. The method of claim 10 , wherein said applying comprises contacting the colloid and the anode after said adsorbing the polymer and prior to said drying.