See biography by V. Bonham-Carter (1964).
At the Royal Institution, Grove met Emma Maria Powles (died 1879) and married her in 1837. Groves's health was never strong and the couple embarked on a tour of the continent for their honeymoon. This sabbatical offered Groves an opportunity to pursue his scientific interests and resulted in his first scientific paper suggesting some novel constructions for electric cells.
In 1839, Grove developed a novel form of electric cell, the Grove cell, which used zinc and platinum electrodes exposed to two acids and separated by a porous ceramic pot. Grove announced the latter development to the Académie des Sciences in Paris in 1839. Later that year, he gave another account of his development at the British Association for the Advancement of Science meeting in Birmingham where it aroused the interest of Michael Faraday. On Faraday's invitiation, Grove presented his discoveries at the prestigious Royal Institution Friday Discourse on 13 March, 1840.
Grove's presentation made his reputation and he was soon proposed for Fellowship of the Royal Society by such distinguished men as William Thomas Brande, William Snow Harris and Charles Wheatstone. Grove also attracted the attention of John Peter Gassiot, a relationship that resulted in Grove becoming the first professor of experimental philosophy at the London Institution in 1841. Grove's inaugural lecture in 1842 was the first announcement of what Grove called the correlation of physical forces, in modern terms, the conservation of energy.
In 1842, Grove developed the first fuel cell (which he called the gas voltaic battery), which produced electrical energy by combining hydrogen and oxygen, and described it using his correlation theory. In developing the cell and showing that steam could be disassociated into oxygen and hydrogen, and the process reversed, he was the first person to demonstrate the thermal dissociation of molecules into their constituent atoms. The first demonstration of this effect, he gave privately to Faraday, Gassiot and Edward William Brayley, his scientific editor. His work also led him to early insights into the nature of ionisation.
Also in the 1840s, Grove collaborated with Gassiot at the London Institution on photography and the Daguerreotype and calotype processes. Inspired by his legal practice, he presciently observed:
In 1852, he discovered striae, dark bands that occur in electrical breakdown, and investigated their character, presenting his work in an 1858 Bakerian lecture.
James Prescott Joule had been inspired to his investigations into the mechanical equivalent of heat by comparing the mass of coal consumed in a steam engine with the mass of zinc consumed in a Grove battery in performing a common quantity of mechanical work. Grove was certainly familiar with William Thomson's theoretical analysis of Joule's experimental results and Thomson's immature suggestions of conservation of energy. Thomson's public champion, Peter Guthrie Tait was initially a supporter of Grove's ideas but later dismissed them with some coolness.
Though Groves's ideas were forerunners of the theory of the conservation of energy, they were qualitative, unlike the quantitative investigations of Joule or Julius Robert von Mayer. His ideas also shaded into broader speculation, such as the nature of Olbers's paradox, which he may have discovered for himself rather than through a direct knowledge.
Grove also speculated that other forms of energy were yet to be discovered "as far certain as certain can be of any future event."
A charter committee had already been established and Grove joined it. Groves's fellow campaigners included Gassiot, Leonard Horner and Edward Sabine and their principal objectives were for the number of new Fellows to be subject to an annual limit and limitation of the power of nomination to the Council. The reformers' success in 1847 led to the resignation of several key conservatives and the establishment of Grove and his associates with domination of the Council. To celebrate, the reformers founded the Philosophical Club.
Though the Philosophical Club succeeded in ensuring that William Parsons, 3rd Earl of Rosse was appointed next President, they failed to get Grove appointed as Secretary. Grove continued to campaign for a single home for all the scientific institutions at Burlington House.
Grove served on a Royal Commission on patent law and on the Metropolitan Commission of Sewers.
He was made judge of the Court of Common Pleas in 1871 and appointed to the Queen's Bench in 1880. He was to have presided at the Cornwall and Devon winter assizes of 1884 which would have entailed him trying the notorious survival cannibalism case of R v. Dudley and Stephens. However, at the last minute he was substituted by Baron Huddleston, possibly because Huddleston was seen as more reliable in ensuring the guilty verdict that the judiciary required. Grove did sit as one of five judges on the final determination of the case in the Divisional Court of the Queen's Bench.
He was a careful, painstaking and accurate judge, courageous and not afraid to assert an independent judicial opinion. However, he was fallible in patent cases where he was prone to become over interested in the technology in question and to be distracted by questioning the litigants as to potential improvements in their devices, even going so far as to suggest his own innovations. He retired from the bench in 1887. His portrait was painted by Helen Donald-Smith 1890s.
Grove, his health perpetually troubled, died at home in London after a long illness. He was buried at Kensal Green Cemetery.