  Growing energy storage demands on lithium-ion batteries necessitate
exploration of new electrochemical materials as next-generation battery
electrode materials. In this work, we investigate the previously unexplored
electrochemical properties of earth-abundant and tunable Zn1-xSn1+xN2 (x = -0.4
to x = 0.4) thin films, which show high electrical conductivity and high
gravimetric capacity for Li insertion. Enhanced cycling performance is achieved
compared to previously published end-members Zn3N2 and Sn3N4, showing decreased
irreversible loss and increased total capacity and cycle stability. The average
reversible capacity observed is > 1050 mAh/g for all compositions and 1220
mAh/g for Zn-poor (x = 0.2) films. Extremely Zn-rich films (x = -0.4) show
improved adhesion; however, Zn-rich films undergo a phase transformation on the
first cycle. Zn-poor and stoichiometric films do not exhibit significant phase
transformations which often plague nitride materials and show no required
overpotential at the 0.5 V plateau. Cation composition x is explored as a
mechanism for tuning relevant mechanical and electrochemical properties, such
as capacity, overpotential, phase transformation, electrical conductivity, and
adhesion. The lithiation/delithiation experiments confirm the reversible
electrochemical reactions. Without any binding additives, the as-deposited
electrodes delaminate resulting in fast capacity degradation. We demonstrate
the mechanical nature of this degradation through decreased electrode thinning,
resulting in cells with improved cycling stability due to increased mechanical
stability. Combining composition and electrochemical analysis, this work
demonstrates for the first time composition dependent electrochemical
properties for the ternary Zn1-xSn1+xN2 and proposes earth-abundant ternary
nitride anodes for increased reversible capacity and cycling stability.
