Solid state cell wherein an anode, solid electrolyte and cathode each comprise a cubic-close-packed framework structure
AssigneeSouth African Inventions Development Corporation
InventorsMichael M. Thackeray, John B. Goodenough
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Abstract
The invention provides an electrochemical cell wherein an anode, solid electrolyte and cathode each comprise a cubic-close-packed framework structure having, as its basic structural unit, a unit of the formula (B.sub.2)X.sub.4.sup.n- which is the structural unit of an A(B.sub.2)X.sub.4 spinel. The structure accommodates active cations M.sup.+ capable of diffusion therethrough. The invention also extends to electrodes and electrolytes of the above type for use in such cells.
Claims23
An electrochemical cell which comprises an anode and a cathode coupled together by a solid electrolyte, the anode and cathode being electronically conducting and the electrolyte being electronically insulating and each of said anode, cathode and electrolyte comprising a cubic-close-packed host framework structure having, as its basic structural unit, a unit of the formula (B.sub.2)X.sub.4.sup.n-, where (B.sub.2)X.sub.4.sup.n- is the structural unit of a spinel, the X anions of said host framework structure being arranged in cubic-close-packed fashion to form a negatively charged anion array, said host framework structure accommodating, within its interconnected interstitial spaces, electrochemically active cations M.sup.+ capable of diffusion through the framework structure, wherein:
- B is a metal cation;
- X is an anion selected from the group VIa or group VIIa elements;
- M is a cation selected from the group Ia or group Ib elements;
- and
- n- refers to the overall charge of the structural unit (B.sub.2)X.sub.4 of the host framework structure, the B cations of the anode being more electropositive than those of the cathode.
An anode for an electrochemical cell, which anode is electronically conducting and comprises a cubic-close-packed host framework structure having, as its basic structural unit, a unit of the formula (B.sub.2)X.sub.4.sup.n-, where (B.sub.2)X.sub.4.sup.n- is the structural unit of a spinel, the X anions of said host framework structure being arranged in cubic-close-packed fashion to form a negatively charged anion array, said host framework accommodating, within its interconnected interstitial spaces, electrochemically active cations M.sup.+ capable of diffusion through the framework structure, wherein:
- B is a metal cation;
- X is an anion selected from the group VIa or group VIIa elements;
- M is a cation selected from the group Ia or group Ib elements;
- and
- n- refers to the overall charge of the structural unit (B.sub.2)X.sub.4 of the host framework structure.
A solid electrolyte for an electrochemical cell, which solid electrolyte is electronically insulating and comprises a cubic-close-packed host framework structure having as its basic structural unit a unit of the formula (B.sub.2)X.sub.4.sup.n-, where (B.sub.2)X.sub.4.sup.n- is the structural unit of a spinel, the X anions of said host framework structure being arranged in cubic-close-packed fashion to form a negatively charged anion array, said host framework structure accommodating, within its interconnected interstitial spaces, electrochemically active cations M.sup.+ capable of diffusion through the framework structure, wherein:
- B is a metal cation;
- X is an anion selected from the group VIa or group VIIa elements;
- M is a cation selected from the group Ia or group Ib elements;
- and
- n- refers to the overall charge of the structural unit (B.sub.2)X.sub.4 of the host framework structure.
A cathode for an electrochemical cell, which cathode is electronically conducting and comprises a cubic-close-packed host framework structure having, as its basic structural unit, a unit of the formula (B.sub.2)X.sub.4.sup.n-, where (B.sub.2)X.sub.4.sup.n- is the structural unit of an A(B.sub.2)X.sub.4 spinel, the X anions of said host framework being arranged in cubic-close-packed fashion to form a negatively charged anion array, said host framework structure, when the cathode is at least partially charged, accommodating within its interconnected interstitial spaces, both the A cations of said A(B.sub.2)X.sub.4 spinel, and additional electrochemically active cations M.sup.+ capable of diffusion through the framework structure, wherein:
- A is a cation of H or Li;
- B is a metal cation;
- X is an anion selected from the group VIa or group VIIa elements;
- M is a cation selected from the group Ia or group Ib elements;
- and
- n- refers to the overall charge of the structural unit (B.sub.2)X.sub.4 of the host framework structure.
An electrochemical cell which comprises an anode and a compatible cathode coupled together by a compatible electrolyte, the anode being electronically conducting and comprising a cubic-close-packed host framework structure having, as its basic structural unit, a unit of the formula (B.sub.2)X.sub.4.sup.n-, where (B.sub.2)X.sub.4.sup.n- is the structural unit of a spinel, the X anions of said host framework structure being arranged in cubic-close-packed fashion to form a negatively charged anion array, said host framework accommodating, within its interconnected interstitial spaces, electrochemically active cations M.sup.+ capable of diffusion through the framework structure, wherein:
- B is a metal cation;
- X is an anion selected from the group VIa or group VIIa elements;
- M is a cation selected from the group Ia or group Ib elements;
- and
- n- refers to the overall charge of the structural unit (B.sub.2)X.sub.4 of the host framework structure.
An electrochemical cell which comprise an anode coupled to the compatible cathode by a compatible electrolyte, the electrolyte being a solid electrolyte which is electronically insulating and comprises a cubic-close-packed host framework structure having, as its basic structural unit, a unit of the formula (B.sub.2)X.sub.4.sup.n-, where (B.sub.2)X.sub.4.sup.n- is the structural unit of a spinel, the X anions of said host framework structure being arranged in cubic-close-packed fashion to form a negatively charged anion array, said host framework structure accommodating, within its interconnected interstitial spaces, electrochemically active cations M.sup.+ capable of diffusion through the framework structure, wherein:
- B is a metal cation;
- X is an anion selected from the group VIa or group VIIa elements;
- M is a cation selected from the group Ia or group Ib elements;
- and
- n- refers to the overall charge of the structural unit (B.sub.2)X.sub.4 of the host framework structure.
An electrochemical cell which comprises an anode coupled to a compatible cathode by a compatible electrolyte, the cathode being electronically conducting and comprising and comprises a cubic-close-packed host framework structure having, as its basic structural unit, a unit of the formula (B.sub.2)X.sub.4.sup.n-, where (B.sub.2)X.sub.4.sup.n- is the structural unit of an A(B.sub.2)X.sub.4 spinel, the X anions of said host framework being arranged in cubic-close-packed fashion to form a negatively charged anion array, said host framework structure, when the cathode is at least partially charged, accommodating within its interconnected interstitial spaces, both the A cations of said A(B.sub.2)X.sub.4 spinel, and additional electrochemically active cations M.sup.+ capable of diffusion through the framework structure, wherein:
- A is a cation of H or Li;
- B is a metal cation;
- X is an anion selected from the group VIa or group VIIa elements;
- M is a cation selected from the group Ia or group Ib elements;
- and
- n- refers to the overall charge of the structural unit (B.sub.2)X.sub.4 of the host framework structure.
Dependencies are inferred from the claim text.